ORCID Profile
0000-0001-7124-2718
Current Organisations
RMIT University
,
Hefei University of Technology
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Functional Materials | Electronic and Magnetic Properties of Condensed Matter; Superconductivity | Condensed Matter Physics | Nanoscale Characterisation | Nanomanufacturing | Photonics and Electro-Optical Engineering (excl. Communications) | Physical Chemistry of Materials | Transition Metal Chemistry | Nanotechnology | Inorganic Chemistry | Materials Engineering | Photonics, Optoelectronics and Optical Communications | Degenerate Quantum Gases and Atom Optics | Condensed Matter Characterisation Technique Development | Nanoelectronics
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Physical Sciences | Expanding Knowledge in Engineering | Expanding Knowledge in Technology | Management of Greenhouse Gas Emissions from Information and Communication Services | Energy Conservation and Efficiency not elsewhere classified | Commercial Energy Conservation and Efficiency | Solar-Photovoltaic Energy | Expanding Knowledge in the Chemical Sciences | Integrated Circuits and Devices |
Related Links
Publications
Carrier and thickness mediated ferromagnetism in chiral magnet Mn1/3TaS2 nanoflakes
Publisher: AIP Publishing
Date: 20-03-2023
DOI: 10.1063/5.0119850
Abstract: Layered chiral magnets with broken spatial inversion symmetry (SIS) enable chiral spin textures to occur in atomically thin layers. However, most layered materials retain SIS during their crystallization. Here, we demonstrate that SIS can be broken in a layered transition metal dichalcogenide TaS2 by intercalating Mn atoms. A chiral magnetic phase in Mn1/3TaS2 has, thus, been realized. This phase enables a nonzero Dzyaloshinskii–Moriya interaction, which in turn gives rise to large topological Hall effects (THEs) below 50 K. Both the ferromagnetism and THE can be tuned at low temperatures by modulating the carrier density via a protonic gate. Measured at 20 K with Vg = −4.7 V applied to the gate and electron doping density of 1.7 × 1022 cm−3, the maximum THE was almost double that recorded with no gate voltage applied. By further reducing the s le thicknesses, both the Curie temperature Tc and the longitudinal magnetoresistance can be significantly modulated. This is consistent with the theory of critical behavior. Our work highlights the ability to control both magnetism and chiral spin textures in Mn1/3TaS2 nanoflakes. Applying this discovery may lead to a variety of practical van der Waals heterostructure devices.
The structure of the CoS2 (100)-(1x1) surface
Publisher: IOP Publishing
Date: 26-03-2007
The electronic band structure of CoS2
Publisher: IOP Publishing
Date: 26-03-2007
Nanograting-assisted generation of surface plasmon polaritons in Weyl semimetal WTe2
Publisher: Elsevier BV
Date: 12-2018
Magnetic and electronic properties of La1-xSrxCoO3 single crystals across the percolation metal-insulator transition
Publisher: American Physical Society (APS)
Date: 12-10-2006
Defect-induced negative magnetoresistance and surface state robustness in the topological insulator BiSbTeSe2
Publisher: American Physical Society (APS)
Date: 17-12-2014
Room temperature ferromagnetism of bulk polycrystalline (In0.85-xSnxFe0.15)2O3: Charge carrier mediated or oxygen vacancy mediated?
Publisher: AIP Publishing
Date: 07-09-2009
DOI: 10.1063/1.3222867
Abstract: Four bulk polycrystalline (In0.85−xSnxFe0.15)2O3 s les with x=0, 0.01, 0.03, and 0.05 were synthesized, where carrier concentration n was controlled by varying Sn doping concentration x. Strong room temperature ferromagnetism was observed. A systematic characterization and analysis of structure, purity, magnetic, and transport properties indicates that ferromagnetism is due to neither impurities nor charge carriers. The four s les were annealed in air and high vacuum alternately. The ferromagnetism signal disappears and appears accordingly. Based on these results, we conclude that room temperature ferromagnetism in (In0.85−xSnxFe0.15)2O3 system is closely and directly related to oxygen vacancies in the s les.
Composition controlled spin polarization in Co1-xFexS2 alloys
Publisher: IOP Publishing
Date: 04-07-2007
DOI: 10.1088/0953-8984/19/31/315219
Abstract: The transition metal (TM) chalcogenides of the form TMX(2) (X = S or Se) have been studied for decades due to their interesting electronic and magnetic properties such as metamagnetism and metal-insulator transitions. In particular, the Co(1-x)Fe(x)S(2) alloys were the subject of investigation in the 1970s due to general interest in itinerant ferromagnetism. In recent years (2000-present) it has been shown, both by electronic structure calculations and detailed experimental investigations, that Co(1-x)Fe(x)S(2) is a model system for the investigation of highly spin polarized ferromagnetism. The radically different electronic properties of the two endpoint compounds (CoS(2) is a narrow bandwidth ferromagnetic metal, while FeS(2) is a diamagnetic semiconductor), in a system forming a substitutional solid solution allows for composition control of the Fermi level relative to the spin split bands, and therefore composition-controlled conduction electron spin polarization. In essence, the recent work has shown that the concept of 'band engineering' can be applied to half-metallic ferromagnets and that high spin polarization can be deliberately engineered. Experiments reveal tunability in both sign and magnitude of the spin polarization at the Fermi level, with maximum values obtained to date of 85% at low temperatures. In this paper we review the properties of Co(1-x)Fe(x)S(2) alloys, with an emphasis on properties of relevance to half-metallicity. Crystal structure, electronic structure, synthesis, magnetic properties, transport properties, direct probes of the spin polarization, and measurements of the total density of states at the Fermi level are all discussed. We conclude with a discussion of the factors that influence, or even limit, the spin polarization, along with a discussion of opportunities and problems for future investigation, particularly with regard to fundamental studies of spintronic devices.
Effect of post annealing process on structural, magnetic and spin dynamics properties of MnFe2O4 nanoparticles
Publisher: Elsevier BV
Date: 06-2023
Evolution with composition of the d-band density of states at the Fermi level in highly spin polarized Co1-xFexS2
Publisher: American Physical Society (APS)
Date: 28-04-2006
Nonlinear antidamping spin-orbit torque originating from intraband transport on the warped surface of a topological insulator
Publisher: American Physical Society (APS)
Date: 17-02-2022
Electrically controlled superconductor-to-failed insulator transition and giant anomalous Hall effect in kagome metal CsV3Sb5 nanoflakes
Publisher: Springer Science and Business Media LLC
Date: 08-02-2023
DOI: 10.1038/S41467-023-36208-6
Abstract: The electronic correlations (e.g. unconventional superconductivity (SC), chiral charge order and nematic order) and giant anomalous Hall effect (AHE) in topological kagome metals AV 3 Sb 5 (A = K, Rb, and Cs) have attracted great interest. Electrical control of those correlated electronic states and AHE allows us to resolve their own nature and origin and to discover new quantum phenomena. Here, we show that electrically controlled proton intercalation has significant impacts on striking quantum phenomena in CsV 3 Sb 5 nanodevices mainly through inducing disorders in thinner nanoflakes and carrier density modulation in thicker ones. Specifically, in disordered thin nanoflakes (below 25 nm), we achieve a quantum phase transition from a superconductor to a “failed insulator” with a large saturated sheet resistance for T → 0 K. Meanwhile, the carrier density modulation in thicker nanoflakes shifts the Fermi level across the charge density wave (CDW) gap and gives rise to an extrinsic-intrinsic transition of AHE. With the first-principles calculations, the extrinsic skew scattering of holes in the nearly flat bands with finite Berry curvature by multiple impurities would account for the giant AHE. Our work uncovers a distinct disorder-driven bosonic superconductor-insulator transition (SIT), outlines a global picture of the giant AHE and reveals its correlation with the unconventional CDW in the AV 3 Sb 5 family.
Interface and Surface Cation Stoichiometry Modified by Oxygen Vacancies in Epitaxial Manganite Films
Publisher: Wiley
Date: 15-06-2012
The kinetic energy dependent effective Debye temperature for CoS2(100)
Publisher: Elsevier BV
Date: 03-2008
Strong thermal-history-dependent magnetoresistance behavior in Ni49.5Mn34.5In16
Publisher: AIP Publishing
Date: 15-09-2009
DOI: 10.1063/1.3225578
Abstract: The thermal-history-dependent (THD) isothermal magnetoresistance (MR) behavior of Ni49.5Mn34.5In16 metamagnetic shape memory alloy is investigated. Irreversibility in isothermal MR is observed in reverse martensitic transformation temperature range, while an intriguing “overshooting” phenomenon is observed in forward martensitic transformation temperature range, showing a strong thermal-history dependence of MR behavior. Such a THD MR behavior can be explained in terms of phase coexistence, THD metastable phase, and magnetic-field-induced phase transition.
A superferromagnetic approach for rapidly quenched Y60Fe30Al10alloys
Publisher: IOP Publishing
Date: 08-05-2000
Cluster-glass behaviour of the substituted molybdenum ferrite: a magnetic and Mössbauer study
Publisher: IOP Publishing
Date: 22-11-2000
Defects Engineering Induced Ultrahigh Magnetization in Rare Earth Element Nd‐doped MoS 2
Publisher: Wiley
Date: 17-12-2020
Gate-tuned quantum oscillations of topological surface states in β-Ag2Te
Publisher: Springer Science and Business Media LLC
Date: 27-01-2015
DOI: 10.1038/SREP08062
Ballistic heat transport in nanocontacts
Publisher: American Physical Society (APS)
Date: 07-01-2010
Magnetic anisotropy in the ferromagnetic Cu-doped ZnO nanoneedles
Publisher: AIP Publishing
Date: 15-01-2007
DOI: 10.1063/1.2433028
Abstract: Copper-doped ZnO (ZnO:Cu) nanoneedles exhibiting room-temperature ferromagnetism were fabricated by an ion beam technique using Cu plate and ZnO film. A saturated magnetization moment of 0.698emu∕cm3 was found in the nanoneedles when a field of 10kOe was applied perpendicular to the substrate, which was 15% larger than the field applied parallel to the substrate. The magnetic ordering of the nanoneedles was enhanced significantly to 0.968emu∕cm3 after annealing of 400°C for 20min. However, the magnetic anisotropy at high field is vanished but an “easy plane” ferromagnetism becomes apparent at low field region. The possible mechanisms of the magnetic ordering and anisotropy in the ZnO:Cu nanoneedles are discussed.
Anomalous magnetic viscosity in bulk-amorphous materials
Publisher: Elsevier BV
Date: 12-1999
Epitaxial growth of CoFe2O4 on SrTiO3 (100) and MgO (100) substrates without buffer layer by laser molecular beam epitaxy technique
Publisher: Elsevier BV
Date: 2011
Indications of surface-dominated transport in single crystalline nanoflake devices of topological insulator Bi1.5Sb0.5Te1.8Se1.2
Publisher: American Physical Society (APS)
Date: 22-05-2203
Negative magnetization, magnetic anisotropy and magnetic ordering studies on Al3+-substituted copper ferrite
Publisher: Elsevier BV
Date: 04-2011
Temperature controlled c axis elongated low symmetry phase BiFeO3 thin film on STO substrate
Publisher: AIP Publishing
Date: 2013
DOI: 10.1063/1.4789399
Abstract: BiFeO3 thin films with a mixture of tunable R-like and c axis elongated low symmetry phase (T-like phase) are fabricated on STO (001) substrate through controlling of the substrate temperature. Almost pure T-like phase can be grown on STO substrate at 600°C. Comparing with the situations on LAO (001), it is found that, strains from the LAO substrate may be the only reason that induces the T-like phase at higher temperatures. At lower temperatures, the island growth induced strains alone can also generate T-like phase on STO substrate.
Electronic structure of Co1–xFexS2
Publisher: Wiley
Date: 07-2006
Magnetic relaxation in spinel Mo-ferrite and Ti substituted Mo-ferrite
Publisher: Springer Science and Business Media LLC
Date: 05-2002
Large linear magnetoresistance and nontrivial band topology in In3Rh
Publisher: AIP Publishing
Date: 15-05-2023
DOI: 10.1063/5.0142095
Abstract: While In3Rh has been predicted to be a three-dimensional Dirac semimetal, experimental studies of its physical properties are lacking. Here, we report the angular-dependent magnetoresistance (MR) measurements of In3Rh single crystals under high magnetic fields up to 32 T. The crystals show large, non-saturating linear MR, and remarkable quantum oscillations with multi-frequencies. Analysis of the quantum oscillations reveals that there are three bands hosting a nontrivial Berry phase, which is corroborated by first-principles calculations. Our work may provide a platform for exploring topological materials in indium-rich transition metal compounds.
Tailoring Dzyaloshinskii–Moriya interaction in a transition metal dichalcogenide by dual-intercalation
Publisher: Springer Science and Business Media LLC
Date: 15-06-2021
DOI: 10.1038/S41467-021-23658-Z
Abstract: Dzyaloshinskii–Moriya interaction (DMI) is vital to form various chiral spin textures, novel behaviors of magnons and permits their potential applications in energy-efficient spintronic devices. Here, we realize a sizable bulk DMI in a transition metal dichalcogenide (TMD) 2H-TaS 2 by intercalating Fe atoms, which form the chiral supercells with broken spatial inversion symmetry and also act as the source of magnetic orderings. Using a newly developed protonic gate technology, gate-controlled protons intercalation could further change the carrier density and intensely tune DMI via the Ruderman–Kittel–Kasuya–Yosida mechanism. The resultant giant topological Hall resistivity $${\\rho }_{{xy}}^{T}$$ ρ x y T of $$1.41{\\mathrm{\\mu}} \\Omega \\cdot {{\\mathrm{cm}}}$$ 1.41 μ Ω ⋅ cm at $${V}_{g}=-5.2{\\mathrm{V}}$$ V g = − 5.2 V (about $$424 \\%$$ 424 % larger than the zero-bias value) is larger than most known chiral magnets. Theoretical analysis indicates that such a large topological Hall effect originates from the two-dimensional Bloch-type chiral spin textures stabilized by DMI, while the large anomalous Hall effect comes from the gapped Dirac nodal lines by spin–orbit interaction. Dual-intercalation in 2H-TaS 2 provides a model system to reveal the nature of DMI in the large family of TMDs and a promising way of gate tuning of DMI, which further enables an electrical control of the chiral spin textures and related electromagnetic phenomena.
Nonvolatile Multistates Memories for High-Density Data Storage
Publisher: American Chemical Society (ACS)
Date: 19-08-2020
Spin Dynamics in Highly Spin Polarized Co1−xFexS2
Publisher: AIP
Date: 2006
DOI: 10.1063/1.2355165
Magnetic and electric transport properties of Nd0.75Sr1.25Co1−xMnxO4
Publisher: AIP Publishing
Date: 15-12-2008
DOI: 10.1063/1.3046673
Abstract: We present the results of a systematic investigation of crystal structure, dc magnetization, ac susceptibility, resistivity, and magnetoresistance (MR) of Nd0.75Sr1.25Co1−xMnxO4 (0≤x≤0.3) polycrystals. All synthesized specimens are indexed in the same tetragonal space group I4/mmm with random occupation of Co and Mn ions at the identical site. The refinement result confirms the tetragonal distortion of the CoO6 octahedron with elongation along the c axis. The substitution of the Mn ions at Co site brings about the suppression of ferromagnetism as well as the enhancement of antiferromagnetism. The coexistence of ferromagnetic double exchange interactions and antiferromagnetic superexchange interactions and the suppression of ferromagnetism with increasing Mn doping are substantiated by the isothermal magnetization hysteresis loops. The result suggests that the substitution creates more antiferromagnetic bonds with superexchange interactions at the expense of the existing Co–O–Co bonds with ferromagnetic double exchange interactions. At low temperature, a crossover from ferromagnetic cluster-glass phase to spin-glass phase is shown in the dc and ac magnetic measurements. For all the specimens, the resistivity ρ(T) follows semiconducting behavior (dρ/dT& ) in the whole measured temperature region. The substitution induces an obvious increase in resistivity, which originates from the diminishing of ferromagnetic double exchange interactions and the localization of charge carriers caused by the disorder for the substitution. The system presents negative MR due to tunneling effect at low temperatures and positive MR at high-temperature range.
Exchange bias as a probe of the incommensurate spin-density wave in epitaxial Fe/Cr(001)
Publisher: American Physical Society (APS)
Date: 12-2006
A second-order ferromagnetic transition in the martensitic state of Ni49.5Mn32.5Cu4Sn14: A critical behavior study
Publisher: AIP Publishing
Date: 15-01-2009
DOI: 10.1063/1.3068180
Abstract: A second-order ferromagnetic transition is observed in the martensitic state of Ni49.5Mn32.5Cu4Sn14 alloy and the critical behavior around the transition is investigated by dc magnetization measurements. With the help of modified Arrott plots, Kouvel–Fisher method, and Widom scaling relation, the values of TcM (ferromagnetic transition temperature in the martensite), and critical exponents: β (associated with the spontaneous magnetization), γ (relevant to the initial susceptibility), and δ (associated with the critical magnetization isotherm) are obtained. The scaling plots show that the obtained values of the critical exponents are reliable. The values of the critical exponents of Ni49.5Mn32.5Cu4Sn14 are different from those predicted by several theoretical models, i.e., mean-field theory, three-dimensional Heisenberg model, and three-dimensional Ising model. The magnetic interactions exhibit two different behaviors: long-range magnetic interaction below TcM and local magnetic interaction above TcM. The change in Mn moments may be responsible for the change in magnetic interactions around TcM.
A magnetic and Mössbauer study of melt-spun Nd60Fe30Al10
Publisher: Elsevier BV
Date: 03-2001
Electric Control of Exchange Bias Effect in FePS3–Fe5GeTe2 van der Waals Heterostructures
Publisher: American Chemical Society (ACS)
Date: 31-07-2022
DOI: 10.1021/ACS.NANOLETT.2C01370
Abstract: Manipulating the exchange bias (EB) effect using an electronic gate is a significant goal in spintronics. The emergence of van der Waals (vdW) magnetic heterostructures has provided improved means to study interlayer magnetic coupling, but to date, these heterostructures have not exhibited electrical gate-controlled EB effects. Here, we report electrically controllable EB effects in a vdW heterostructure, FePS
Quantum Transport in Air-Stable Na3Bi Thin Films
Publisher: American Chemical Society (ACS)
Date: 27-07-2020
Plasmonic Properties and Photoinduced Reflectance of Topological Insulator
Publisher: OSA
Date: 2014
Topological-insulator-based terahertz modulator
Publisher: Springer Science and Business Media LLC
Date: 18-10-2017
DOI: 10.1038/S41598-017-13701-9
Abstract: Three dimensional topological insulators, as a new phase of quantum matters, are characterized by an insulating gap in the bulk and a metallic state on the surface. Particularly, most of the topological insulators have narrow band gaps, and hence have promising applications in the area of terahertz optoelectronics. In this work, we experimentally demonstrate an electronically-tunable terahertz intensity modulator based on Bi 1:5 Sb 0:5 Te 1:8 Se 1:2 single crystal, one of the most insulating topological insulators. A relative frequency-independent modulation depth of ~62% over a wide frequency range from 0.3 to 1.4 THz has been achieved at room temperature, by applying a bias current of 100 mA. The modulation in the low current regime can be further enhanced at low temperature. We propose that the extraordinarily large modulation is a consequence of thermally-activated carrier absorption in the semiconducting bulk states. Our work provides a new application of topological insulators for terahertz technology.
Model of ferromagnetic clusters in amorphous rare earth and transition metal alloys
Publisher: AIP Publishing
Date: 15-06-2001
DOI: 10.1063/1.1371005
Abstract: Experimental results on amorphous rare earth and transition metal alloys suggest the presence of Fe-rich clusters. A model is proposed in which the magnetic units are magnetic clusters. The magnetization of the clusters decreases with the increase of temperature. In this model, there are two critical temperatures, Tcsystem and Tccluster. Tccluster is the Curie temperature of the magnetic clusters, which is also the Curie temperature of the s le. Tcsystem is the measurement of the strength of interactions between clusters. Between Tccluster and Tcsystem, the system exhibits superparamagnetism with strong cluster interactions. The strong cluster interactions result in the ferromagnetic state below the critical temperature (Tcsystem), which is called a cluster ferromagnetism. Our experimental data (magnetization curves and susceptibility values of amorphous Y60Fe30Al10 and Nd60Fe30Al10 ribbons) support the cluster ferromagnetic model. The zero temperature coercivity and the relationship between Tblock and Tcsystem are also discussed in this article.
Spin-dependent band structure effects and measurement of the spin polarization in the candidate half-metal CoS2
Publisher: American Physical Society (APS)
Date: 16-03-2004
Intrinsic phase separation in a single crystal of La0.98Pb0.02Mn0.74Co0.25O3
Publisher: AIP Publishing
Date: 2009
DOI: 10.1063/1.3054172
Abstract: Systematic studies of magnetic, electrical, and thermal transport properties have been performed on a single crystal of La0.98Pb0.02Mn0.74Co0.25O3. From 5 to 500 K, the material system shows three distinct magnetic states, a low-temperature glassing state (from 5 to 185 K), a Griffiths-like ferromagnetic state (from 185 to 326 K), and a single paramagnetic phase above 326 K. The s le shows a semiconducting electrical transport behavior in the whole studied temperature range. With decreasing temperature, magnetoresistance increases rapidly from 290 K and reaches a maximum at 185 K and then decreases continuously with a broad peak in the vicinity of 100 K. Magnetothermopower also presents obvious anomalies at these characteristic temperatures. Both the magnetic and transport properties suggest an intrinsic phase separation in the single crystal.
Experimental evidences of topological surface states of beta-Ag2Te
Publisher: AIP Publishing
Date: 03-2013
DOI: 10.1063/1.4795735
Abstract: We present evidence of topological surface states in β-Ag2Te through first-principles calculations, periodic quantum interference effect and ambipolar electric field effect in single crystalline nanoribbon. Our first-principles calculations show that β-Ag2Te is a topological insulator with a gapless Dirac cone with strong anisotropy. To experimentally probe the topological surface state, we synthesized high quality β-Ag2Te nanoribbons and performed electron transport measurements. The coexistence of pronounced Aharonov-Bohm oscillations and weak Altshuler-Aronov-Spivak oscillations clearly demonstrates coherent electron transport around the perimeter of β-Ag2Te nanoribbon and therefore the existence of topological surface states, which is further supported by the ambipolar electric field effect for devices fabricated by β-Ag2Te nanoribbons. The experimental evidences of topological surface states and the theoretically predicted anisotropic Dirac cone of β-Ag2Te suggest that the material may be a promising candidate of topological insulator for fundamental study and future spintronic devices.
A model for magnetic ordering in inhomogeneous amorphous RE–Fe–Al alloys
Publisher: Elsevier BV
Date: 05-2001
Ferromagnetism in ZnO nanowires derived from electro-deposition on AAO template and subsequent oxidation
Publisher: Wiley
Date: 18-03-2008
Wafer-Sized Ultrathin Gallium and Indium Nitride Nanosheets through the Ammonolysis of Liquid Metal Derived Oxides
Publisher: American Chemical Society (ACS)
Date: 20-12-2019
DOI: 10.1021/JACS.8B11483
Abstract: We report the synthesis of centimeter sized ultrathin GaN and InN. The synthesis relies on the ammonolysis of liquid metal derived two-dimensional (2D) oxide sheets that were squeeze-transferred onto desired substrates. Wurtzite GaN nanosheets featured typical thicknesses of 1.3 nm, an optical bandgap of 3.5 eV and a carrier mobility of 21.5 cm
Majorana zero modes in iron-based superconductors
Publisher: Elsevier BV
Date: 06-2022
Hard magnetic properties and magnetocaloric effect in amorphous NdFeAl ribbons
Publisher: Elsevier BV
Date: 03-2001
Direct visualization of current-induced spin accumulation in topological insulators
Publisher: Springer Science and Business Media LLC
Date: 27-06-2018
DOI: 10.1038/S41467-018-04939-6
Abstract: Charge-to-spin conversion in various materials is the key for the fundamental understanding of spin-orbitronics and efficient magnetization manipulation. Here we report the direct spatial imaging of current-induced spin accumulation at the channel edges of Bi 2 Se 3 and BiSbTeSe 2 topological insulators as well as Pt by a scanning photovoltage microscope at room temperature. The spin polarization is along the out-of-plane direction with opposite signs for the two channel edges. The accumulated spin direction reverses sign upon changing the current direction and the detected spin signal shows a linear dependence on the magnitude of currents, indicating that our observed phenomena are current-induced effects. The spin Hall angle of Bi 2 Se 3 , BiSbTeSe 2 , and Pt is determined to be 0.0085, 0.0616, and 0.0085, respectively. Our results open up the possibility of optically detecting the current-induced spin accumulations, and thus point towards a better understanding of the interaction between spins and circularly polarized light.
Multiferroicity in manganite/titanate superlattices determined by oxygen pressure-mediated cation defects
Publisher: AIP Publishing
Date: 23-04-2013
DOI: 10.1063/1.4802430
Abstract: Increasing demand for spintronic devices, such as high-density memory elements, has generated interest in magnetoelectric coupling and multiferroic materials. In heteroepitaxial structures, magnetoelectric coupling occurs only near the strained interfaces, which is why the interface-rich multiferroic multilayer/superlattice is viewed as one of the most efficient ways to enhance the magnetoelectric coupling coefficient. However, both ferroelectric and ferromagnetic properties are difficult to be maintained when materials are shrunk to ultrathin layers, forming interfacial dead layers and limiting the application of these materials in atomic-scale devices. In this work, we demonstrate that the largely suppressed multiferroic properties of the La0.8Sr0.2MnO3 (16 unit cells)/BaTiO3 (12 unit cells) superlattice correlate with cation defects including both pure edge dislocations and planar defects. This conclusion is reached by combining atomic-resolution electron microscopy, piezoelectric force microscopy, and low-temperature magnetism measurements. Furthermore, it is shown that the density of the observed cation defects can be largely reduced by improving the oxygen off-stoichiometry through increasing oxygen pressure during growth, resulting in robust multiferroic properties. Only by eliminating oxygen vacancies during growth can the ferroic dead layers be further reduced. This work therefore opens the pathway for the integration of ferromagnetic and ferroelectric materials into magnetoelectric devices at diminished length scales.
Stacking-Dependent Interlayer Ferroelectric Coupling and Moiré Domains in a Twisted AgBiP2Se6 Bilayer
Publisher: American Chemical Society (ACS)
Date: 23-02-2022
DOI: 10.1021/ACS.JPCLETT.2C00177
Abstract: Rotation/twisting of bilayers could induce unprecedented new physics due to stacking-dependent electronic properties and interlayer coupling, such as the superconductivity in twisted bilayer graphene, which can find applications in electronics. However, deep understanding at the atomic/electronic levels is limited by the capability of accurate theoretical simulations. Here, from first-principles simulations, we found that the AgBiP
P -type electrical, photoconductive, and anomalous ferromagnetic properties of Cu2O nanowires
Publisher: AIP Publishing
Date: 16-03-2009
DOI: 10.1063/1.3097029
Abstract: Cu 2 O nanowires are synthesized by reduction of CuO nanowires with hydrogen gas. Strong green photoluminescence dominated by band-edge emission is observed. Field effect transistors fabricated from in idual Cu2O nanowires present high on-off ratio (& ) and high mobility (& cm2/V s). Furthermore, the device demonstrates a fast photoelectric response to blue illumination in air at room temperature. In addition, anomalous ferromagnetism appears in Cu2O nanowires, which may originate from the defects in Cu2O nanowires. This work shows the application potentials of the Cu2O nanowires, especially in an electrical and photonic device.
Magnetic proximity effect in the topological insulator BiSbTeSe2
Publisher: Wiley
Date: 03-2015
Correlation between optical absorption redshift and carrier density in phase change materials
Publisher: AIP Publishing
Date: 24-09-2013
DOI: 10.1063/1.4822311
Abstract: Here, we report an optical absorption redshift map for GeTe-Sb2Te3 pseudo-binary alloys. We found that, with phase change from amorphous to crystalline, the observed redshift increases with Ge concentration along pseudo-line of compositions, which directly reflects the enhanced electron delocalization/resonant bonding and increased carrier concentrations in the respective crystal compounds. The measured valence band maximum shift towards the Fermi energy from amorphous to crystalline phase supports the observed similar trend in redshift and carrier density. We show that the correlation between optical redshift and carrier density, attributed to the resonant bonding, can be rationalized by calculating the valence electron concentration, the ionicity, and hybridization.
Origin of Long-Range Ferromagnetic Ordering in Metal–Organic Frameworks with Antiferromagnetic Dimeric-Cu(II) Building Units
Publisher: American Chemical Society (ACS)
Date: 05-10-2012
DOI: 10.1021/JA3077654
Abstract: Even though metal-organic frameworks (MOFs) derived from antiferromagnetic dimeric-Cu(II) building units and nonmagnetic molecular linkers are known to exhibit unexpected ferromagnetic behavior, a comprehensive understanding of the underlying mechanism remains elusive. Using a combined theoretical and experimental approach, here we reveal the origin of the long-range ferromagnetic coupling in a series of MOFs, constructed from antiferromagnetic dimeric-Cu(II) building blocks. Our studies show that the strong localization of copper vacancy states favors spontaneous spin polarization and formation of local moment. These copper vacancy-induced moments are coupled via the itinerant electrons in the conjugated aromatic linkers to establish a long-range ferromagnetic ordering. The proposed mechanism is supported by direct experimental evidence of copper vacancies and the magnetic hysteresis (M-H) loops.
Optical response characteristics arising from delocalized electrons in phase change materials
Publisher: Elsevier BV
Date: 03-2013
Magnetotransport properties of p-type carbon-doped ZnO thin films
Publisher: AIP Publishing
Date: 06-07-2009
DOI: 10.1063/1.3176434
Abstract: Carbon-doped ZnO (ZnO:C) thin films exhibiting Curie temperature above room temperature were fabricated using ion beam technique. The magnetic moment of the ZnO:C films was found to be around 1.35 μB per carbon atom. The ZnO:C films showed p-type conduction with a hole concentration of ∼5×1017 cm−3. In addition, the anomalous Hall effect and negative magnetoresistance can be detected in the ZnO:C films. The magnetotransport properties of the ZnO:C suggested that the films possessed charge carrier spin polarization.
Large Exchange Bias after Zero-Field Cooling from an Unmagnetized State
Publisher: American Physical Society (APS)
Date: 17-02-2011
The structure of the CoS2 (100)-(1 x 1) surface (vol 19, art no 156223, 2007)
Publisher: IOP Publishing
Date: 06-2007
Visible Range Plasmonic Modes on Topological Insulator Nanostructures
Publisher: Wiley
Date: 09-11-2016
A structural, magnetic and Mossbauer investigation on melt-spun Nd0.33 (Fe0.75Al0.25)0.67 ribbons
Publisher: IOP Publishing
Date: 09-12-1999
Large exchange bias obtainable through zero-field cooling from an unmagnetized state in Ni-Mn-Sn alloys
Publisher: AIP Publishing
Date: 15-02-2012
DOI: 10.1063/1.3686717
Abstract: We report a large unusual exchange bias effect occurred after zero-field cooling from an unmagnetized state (ZEB) in Ni-Mn-Sn alloys, in which the maximum ZEB field is about twice as large as that observed in Ni-Mn-In alloys at moderate field range (& 40 kOe). The ZEB field can be tuned by tuning the magnitude of the initial magnetization fields and its sign is strongly dependent on the direction of the initial magnetization fields. Furthermore, the ZEB effect only exists in alloys with volume fraction of superparamagnetic domains less than the percolation limitation in three-dimensional system (∼16%). The present results confirm the universality of this unusual ZEB effect and suggest that NiMn-based alloys provide a platform to obtain this unusual ZEB effect. Such ZEB effect may also exist in other systems with similar magnetic properties.
Massive Dirac fermions and strong Shubnikov–de Haas oscillations in single crystals of the topological insulator Bi2Se3 doped with Sm and Fe
Publisher: American Physical Society (APS)
Date: 30-08-2021
Superior carrier tuning in ultrathin superconducting materials by electric-field gating
Publisher: Springer Science and Business Media LLC
Date: 13-04-2022
Stable ferromagnetism in p-type carbon-doped ZnO nanoneedles
Publisher: AIP Publishing
Date: 28-09-2009
DOI: 10.1063/1.3238289
Abstract: The authors report the synthesis and magnetic properties of carbon-doped ZnO (ZnO:C) nanoneedles. A saturated magnetic moment of 2.16 emu/cm3 was found in the ZnO:C nanoneedles. The s les showed anomalous Hall effect and p-type conduction with a hole concentration of 1.8×1018 cm−3. The ferromagnetism in the ZnO:C nanoneedles could be attributed to C substitution on the O site which introduces hole, so the p-p interaction leads to the strong spin interaction between the C atoms and carriers. It was found that the ferromagnetism and p-type conduction in the ZnO:C nanoneedles were stable in ambient air over a period of 1 year and annealing temperature of up to 100 °C.
Terahertz conductivity of topological surface states in Bi1.5Sb0.5Te1.8Se1.2
Publisher: Springer Science and Business Media LLC
Date: 17-12-2013
DOI: 10.1038/SREP03513
Doping effect on magnetic and transport properties of Pr2−xSrxCoO4
Publisher: IOP Publishing
Date: 09-2008
Annealing induced anomalous electrical transport behavior in SnO2 thin films prepared by pulsed laser deposition
Publisher: AIP Publishing
Date: 30-08-2010
DOI: 10.1063/1.3481376
Abstract: SnO 2 thin films were deposited on quartz substrates by pulsed laser deposition and postannealed at different temperatures in oxygen ambience. X-ray diffraction, Hall measurement, and x-ray photoelectron spectroscopy were employed to investigate the properties of the annealed SnO2 thin films. An anomalous electrical transport behavior as a function of the annealing temperature was observed. Both the growth of the crystal grain and oxygen vacancy density variation in the annealing process have been identified to be responsible for the transition of electrical transport properties.
Impedance spectroscopy and conductivity mechanism of CoFe2O4-Pb(Zr0.53Ti0.47)O-3 composite thick films
Publisher: Elsevier BV
Date: 10-2010
Comparison of magnetic property of Cu-, Al-, and Li-doped ZnO dilute magnetic semiconductor thin films
Publisher: World Scientific Pub Co Pte Lt
Date: 02-2008
DOI: 10.1142/S0218625X08011007
Abstract: The properties of Cu -, Al -, and Li -doped ZnO dilute magnetic semiconductor (DMS) have been analyzed and compared. Zincite with wurtzite structures have been synthesized successfully on SiO 2 (101) and SiO 2 (110) substrates in both the Cu – ZnO and Li – ZnO DMS. The highly textured ZnO (002) peaks were able to form in the Cu – ZnO system at 400°C. However, it formed at even much lower temperature in the Li – ZnO system, that is only 25°C. ZnO (002) peaks in both systems were formed without any impurity phases. However, no crystalline structure is synthesized in the Al – ZnO system. The thin films formed are amorphous. The structural and related magnetic properties of the films were analyzed by XRD, AFM, and VSM. The films were found to be at their highest magnetism at the value of 3.1 emu/cm 3 for Co – ZnO and 2.5 emu/cm 3 for Li – ZnO , synthesized at 400°C, and under 1 × 10 -4 Torr oxygen partial pressure.
Gate-Tuned Interlayer Coupling in van der Waals Ferromagnet Fe3GeTe2 Nanoflakes
Publisher: American Physical Society (APS)
Date: 22-07-2020
Strongly Correlated Properties and Enhanced Thermoelectric Response in Ca3Co4−xMxO9 (M = Fe, Mn, and Cu)
Publisher: American Chemical Society (ACS)
Date: 14-10-2009
DOI: 10.1021/CM902483A
Ferromagnetism in Dilute Magnetic Semiconductors through Defect Engineering: Li-Doped ZnO
Publisher: American Physical Society (APS)
Date: 29-03-2010
Bulk Hard Magnetic Alloys in Nd-Fe-B System Prepared by Casting and Melt Spinning
Publisher: Japan Institute of Metals
Date: 2001
Composition controlled spin polarization in Co1-xFexS2:: Electronic, magnetic, and thermodynamic properties
Publisher: American Physical Society (APS)
Date: 03-04-2006
Observation of intrinsic fluorescence in cobalt ferrite magnetic nanoparticles by Mn2+ substitution and tuning the spin dynamics by cation distribution
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2TC02605H
Abstract: In this work, we report the synthesis and detailed characterization of single-domain, optically active, manganese-substituted cobalt ferrite (CoFe 2 O 4 ) magnetic nanoparticles without any surface functionalization as prospective fluorescent probes for bio-imaging.
Sulfur stoichiometry effects in highly spin polarized CoS2 single crystals
Publisher: AIP Publishing
Date: 05-06-2006
DOI: 10.1063/1.2210291
Abstract: Recent experiments on polycrystalline Co1−xFexS2 demonstrated composition control over the spin polarization by Fermi level manipulation. We report here the growth and characterization of CoS2 single crystals with fine control over the stoichiometry by chemical vapor transport. At the ideal Co:S atomic ratio we observe a minimum in the low temperature resistivity and the x-ray rocking curve width, coincident with a maximum in the residual resistivity ratio and the low temperature magnetoresistance. Point contact Andréev reflection on stoichiometric crystals indicates a spin polarization at the Fermi energy of 64%, a significant increase over the 56% observed in polycrystals.
Oxygen-driven anisotropic transport in ultra-thin manganite films
Publisher: Springer Science and Business Media LLC
Date: 13-11-2013
DOI: 10.1038/NCOMMS3778
Cross-over from weak localization to anti-localization in rare earth doped TRS protected topological insulators
Publisher: Elsevier BV
Date: 2021
Strong uni-directional anisotropy in disordered NiFe2O4
Publisher: Elsevier BV
Date: 06-2000
Microwave spin resonance investigation on the effect of the post-processing annealing of CoFe2O4 nanoparticles
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0NA00156B
Abstract: A novel investigation on the finite-size effects on the spin resonance properties of cobalt ferrite (CoFe 2 O 4 ) nanoparticles has been performed using a room temperature ferromagnetic resonance (FMR) technique.
Antisymmetric magnetoresistance in van der Waals Fe 3 GeTe 2 /graphite/Fe 3 GeTe 2 trilayer heterostructures
Publisher: American Association for the Advancement of Science (AAAS)
Date: 05-07-2019
Abstract: The observation of an antisymmetric magnetoresistance in a trilayer van der Waals heterostructure Fe 3 GeTe 2 /graphite/Fe 3 GeTe 2 .
Anomalous phase change characteristics in Fe-Te materials
Publisher: AIP Publishing
Date: 14-05-2012
DOI: 10.1063/1.4719074
Abstract: Phase change materials have become significantly attractive due to its unique characteristics for its extensive applications. In this paper, a kind of phase change material, which consists of Fe and Te components, is developed. The crystallization temperature of the Fe-Te materials is 180 °C for Fe1.19Te and can be adjusted by the Fe/Te ratio. High-speed phase change in the Fe-Te materials has been demonstrated by nanosecond laser irradiation. Comparing to conventional phase change materials, the Fe-Te materials exhibit an anomalous optical property that has higher reflectivity at amorphous than crystalline state, which is useful for data storage design.
Exchange bias and its training effect in the martensitic state of bulk polycrystalline Ni49.5Mn34.5In16
Publisher: AIP Publishing
Date: 15-08-2008
DOI: 10.1063/1.2973187
Abstract: Exchange bias phenomena are observed in the bulk polycrystalline Ni49.5Mn34.5In16 alloy in which ferromagnetic and antiferromagnetic phases coexist in the martensitic state. Both the exchange bias field and coercivity are strongly dependent on temperature. The training effect of the exchange bias is found to be very small in the present alloy and can be explained by the depinning of uncompensated antiferromagnet spins. These results suggest that the ferromagnetic and antiferromagnetic domains couple at the interfaces and as a result induce the exchange bias. Such behavior is an addition to the multifunctional properties of the Ni49.5Mn34.5In16 ferromagnetic shape memory alloy.
Nonlinear Ballistic Response of Quantum Spin Hall Edge States
Publisher: American Physical Society (APS)
Date: 08-11-2021
Dielectric dynamics of epitaxial BiFeO3 thin films
Publisher: AIP Publishing
Date: 17-05-2012
DOI: 10.1063/1.4721670
Abstract: We report the detailed study on the low temperature dielectric dynamics of the epitaxial BiFeO3 thin films grown on Nb-doped SrTiO3 substrate. The results indicate that the contributions from the thin film dominate the dielectric response, although it comes from both the thin film and the electrode interface. Furthermore, the origins of the low temperature dielectric anomalies are investigated with electric circuit fittings. A possible phase transition at 210 K is revealed from analysis with dielectric loss tangent. The dielectric constants obtained from the constant phase elements (CPEs) are more than 400 even at low temperatures. Finally, the physical significances of the CPE model are discussed.
Thermal-Induced Microstructural Changes of Nickel−Iron Cyanide
Publisher: American Chemical Society (ACS)
Date: 31-08-2000
DOI: 10.1021/JP000881W
Enhanced magnetoresistance through magnetic-field-induced phase transition in Ni2MnGa co-doped with Co and Mn
Publisher: Elsevier BV
Date: 03-2010
Optical and ferromagnetic characteristics of Mn doped ZnO thin films grown by filtered cathodic vacuum arc technique
Publisher: Elsevier BV
Date: 09-2010
Anisotropic magnetoresistance in topological insulator Bi1.5Sb0.5Te1.8Se1.2/CoFe heterostructures
Publisher: AIP Publishing
Date: 30-11-2012
DOI: 10.1063/1.4769894
Abstract: Topological insulator is composed of an insulating bulk state and time reversal symmetry protected two-dimensional surface states. One of the characteristics of the surface states is the locking between electron momentum and spin orientation. Here, we report a novel in-plane anisotropic magnetoresistance in topological insulator Bi1.5Sb0.5Te1.8Se1.2/CoFe heterostructures. To explain the novel effect, we propose that the Bi1.5Sb0.5Te1.8Se1.2/CoFe heterostructure forms a spin-valve or Giant magnetoresistance device due to spin-momentum locking. The novel in-plane anisotropic magnetoresistance can be explained as a Giant magnetoresistance effect of the Bi1.5Sb0.5Te1.8Se1.2/CoFe heterostructures.
Amorphous magnetic RE-Fe-Al alloys
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2001
DOI: 10.1109/20.951215
Anomalous Hall effect in Cu and Fe codoped In2O3 and ITO thin films
Publisher: Elsevier BV
Date: 08-2009
Coupled structural/magnetocrystalline anisotropy transitions in the doped perovskite cobaltite Pr1-xSrxCoO3
Publisher: American Physical Society (APS)
Date: 15-06-2009
Gate-Controlled Magnetic Phase Transition in a van der Waals Magnet Fe5GeTe2
Publisher: American Chemical Society (ACS)
Date: 21-06-2021
Hard magnetic properties in nanoflake van der Waals Fe3GeTe2
Publisher: Springer Science and Business Media LLC
Date: 19-04-2018
DOI: 10.1038/S41467-018-04018-W
Abstract: Two-dimensional van der Waals materials have demonstrated fascinating optical and electrical characteristics. However, reports on magnetic properties and spintronic applications of van der Waals materials are scarce by comparison. Here, we report anomalous Hall effect measurements on single crystalline metallic Fe 3 GeTe 2 nanoflakes with different thicknesses. These nanoflakes exhibit a single hard magnetic phase with a near square-shaped magnetic loop, large coercivity (up to 550 mT at 2 K), a Curie temperature near 200 K and strong perpendicular magnetic anisotropy. Using criticality analysis, the coupling length between van der Waals atomic layers in Fe 3 GeTe 2 is estimated to be ~5 van der Waals layers. Furthermore, the hard magnetic behaviour of Fe 3 GeTe 2 can be well described by a proposed model. The magnetic properties of Fe 3 GeTe 2 highlight its potential for integration into van der Waals magnetic heterostructures, paving the way for spintronic research and applications based on these devices.
Enhanced static and dynamic magnetic properties of PEG-400 coated CoFe2−xErxO4 (0.7 ≤ x ≤0) nanoferrites
Publisher: Elsevier BV
Date: 12-2021
Monte Carlo simulation of a cluster system with strong interaction and random anisotropy
Publisher: American Physical Society (APS)
Date: 07-11-2001
Ordered-vacancy-enabled indium sulphide printed in wafer-scale with enhanced electron mobility
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9MH01365B
Abstract: The unique and long-range ordered-vacancy structure in wafer-scale grown single-unit-cell-thick In 2 S 3 facilitates excellent electronic performance.
Co1-xFexS2: A tunable source of highly spin-polarized electrons
Publisher: American Physical Society (APS)
Date: 11-02-2005
Intrinsically core-shell plasmonic dielectric nanostructures with ultrahigh refractive index
Publisher: American Association for the Advancement of Science (AAAS)
Date: 04-03-2016
Abstract: A new type of plasmonic nanostructures with topologically protected metallic shells and high–refractive index dielectric cores.
Growth and structure investigation of multiferroic superlattices: [(La0.8Sr0.2MnO3)4n/(BaTiO3)3n]m
Publisher: Elsevier BV
Date: 08-2010
Visible Range Plasmons in Topological Insulators
Publisher: OSA
Date: 2016
Colossal Magnetization and Giant Coercivity in Ion-Implanted (Nb and Co) MoS2 Crystals
Publisher: American Chemical Society (ACS)
Date: 16-12-2020
Liquid metal-based synthesis of high performance monolayer SnS piezoelectric nanogenerators
Publisher: Springer Science and Business Media LLC
Date: 10-07-2020
DOI: 10.1038/S41467-020-17296-0
Abstract: The predicted strong piezoelectricity for monolayers of group IV monochalcogenides, together with their inherent flexibility, makes them likely candidates for developing flexible nanogenerators. Within this group, SnS is a potential choice for such nanogenerators due to its favourable semiconducting properties. To date, access to large-area and highly crystalline monolayer SnS has been challenging due to the presence of strong inter-layer interactions by the lone-pair electrons of S. Here we report single crystal across-the-plane and large-area monolayer SnS synthesis using a liquid metal-based technique. The characterisations confirm the formation of atomically thin SnS with a remarkable carrier mobility of ~35 cm 2 V −1 s −1 and piezoelectric coefficient of ~26 pm V −1 . Piezoelectric nanogenerators fabricated using the SnS monolayers demonstrate a peak output voltage of ~150 mV at 0.7% strain. The stable and flexible monolayer SnS can be implemented into a variety of systems for efficient energy harvesting.
Manipulation of ferromagnetism in intrinsic two-dimensional magnetic and nonmagnetic materials
Publisher: Elsevier BV
Date: 12-2022
Sign-tunable exchange bias effect in proton-intercalated Fe3GaTe2 nanoflakes
Publisher: American Physical Society (APS)
Date: 20-04-2023
Imaging Domain Reversal in an Ultrathin Van der Waals Ferromagnet
Publisher: Wiley
Date: 23-08-2020
Ultraviolet and visible range plasmonics in the topological insulator Bi1.5Sb0.5Te1.8Se1.2
Publisher: Springer Science and Business Media LLC
Date: 08-10-2014
DOI: 10.1038/NCOMMS6139
Abstract: The development of metamaterials, data processing circuits and sensors for the visible and ultraviolet parts of the spectrum is h ered by the lack of low-loss media supporting plasmonic excitations. This has driven the intense search for plasmonic materials beyond noble metals. Here we show that the semiconductor Bi1.5Sb0.5Te1.8Se1.2, also known as a topological insulator, is also a good plasmonic material in the blue-ultraviolet range, in addition to the already-investigated terahertz frequency range. Metamaterials fabricated from Bi1.5Sb0.5Te1.8Se1.2 show plasmonic resonances from 350 to 550 nm, while surface gratings exhibit cathodoluminescent peaks from 230 to 1,050 nm. The observed plasmonic response is attributed to the combination of bulk charge carriers from interband transitions and surface charge carriers of the topological insulator. The importance of our result is in the identification of new mechanisms of negative permittivity in semiconductors where visible range plasmonics can be directly integrated with electronics.
Room-Temperature Magnetic Phase Transition in an Electrically Tuned van der Waals Ferromagnet
Publisher: American Physical Society (APS)
Date: 17-10-2023
High Coercivity and Magnetization in WSe2 by Codoping Co and Nb
Publisher: Wiley
Date: 22-08-2019
Abstract: Introducing ferromagnetism in transition metal dichalcogenides has attracted lots of attention due to the possible applications in spintronics devices. Generally, single magnetic element doping is used to introduce magnetism. However, mostly, weak ferromagnetism is observed. In this work, codoping of two kinds of transition metals (Nb and Co) into WSe
Electrically Tunable In-Plane Anisotropic Magnetoresistance in Topological Insulator BiSbTeSe2 Nanodevices
Publisher: American Chemical Society (ACS)
Date: 11-02-2015
DOI: 10.1021/NL504956S
Abstract: We report tunable in-plane anisotropic magnetoresistance (AMR) in nanodevices based on topological insulator BiSbTeSe2 (BSTS) nanoflakes by electric gating. The AMR can be changed continuously from negative to positive when the Fermi level is manipulated to cross the Dirac point by an applied gate electric field. We also discuss effects of the gate electric field, current density, and magnetic field on the in-plane AMR with a simple physical model, which is based on the in-plane magnetic field induced shift of the spin-momentum locked topological two surface states that are coupled through side surfaces and bulk weak antilocalization (WAL). The large, tunable and bipolar in-plane AMR in BSTS devices provides the possibility of fabricating more sensitive logic and magnetic random access memory AMR devices.
Correlation between the Structural Distortions and Thermoelectric Characteristics in La1−xAxCoO3(A = Ca and Sr)
Publisher: American Chemical Society (ACS)
Date: 05-04-2010
DOI: 10.1021/IC902072V
Abstract: Detailed structures and thermoelectric (TE) properties are investigated for the perovskite La(1-x)Ca(x)CoO(3) and La(1-x)Sr(x)CoO(3) with 0 <or= x <or= 0.3. The monoclinic crystal structures for all s les are refined from powder X-ray diffraction, which reveals that the La(1-x)Sr(x)CoO(3) series has smaller global distortions but larger local distortions. The different structural distortions strongly influence the transport and TE properties in terms of resistivity, thermopower, thermal conductivity, bandwidth, and effective mass as well as electronic correlation. These results unambiguously demonstrate a close correlation between the structural distortions and TE characteristics in this family. Furthermore, a new approach is suggested to improve the TE performance by controlling the structure factors in such strongly correlated oxide systems. The effects of the spin-state transition of Co ions on the TE properties are also discussed.
Tunable artificial topological Hall effects in van der Waals heterointerfaces
Publisher: American Physical Society (APS)
Date: 11-04-2022
Temperature-dependent ultrafast carrier and phonon dynamics of topological insulator Bi1.5Sb0.5Te1.8Se1.2
Publisher: AIP Publishing
Date: 26-05-2014
DOI: 10.1063/1.4879831
Abstract: Using ultrafast optical pump-probe technique, we studied the temperature-dependent carrier and phonon dynamics of the topological insulator Bi1.5Sb0.5Te1.8Se1.2 single-crystal from 10 K to 300 K. Two relaxation processes of carriers and coherent optical/acoustic phonons have been observed. By using the two-temperature model, we are able to attribute the fast (∼ps) relaxation component to carrier-phonon coupling involving carriers in the conduction band. We also studied the temperature dependence of the dephasing time and frequency of optical phonon, and the optical penetration depth of Bi1.5Sb0.5Te1.8Se1.2.
Giant room-temperature modulation of magnetic anisotropy by electric fields in CoFeB/(011)-PMN-PT multiferroic heterostructures with two distinct initial magnetic anisotropies
Publisher: AIP Publishing
Date: 18-08-2023
DOI: 10.1063/5.0159946
Abstract: This paper reports that the in situ growth magnetic field (Hg) during magnetic-phase CoFeB deposition impacts the electric-field control of magnetic anisotropy in Co40Fe40B20/(011)-Pb(Mg1/3Nb2/3)0.7Ti0.3O3 [CoFeB/(011)-PMN-PT] composite multiferroic heterostructures at room temperature. In the Hg1 mode (in situ Hg along the [011¯] direction of the ferroelectric PMN-PT substrate), the electric-field-controlled modulation ratios of the magnetic coercivity HC and saturation magnetic field HS are approximately −47% and +156%, respectively. However, in the Hg2 mode (in situ Hg along the [100] direction of the ferroelectric PMN-PT substrate) of the CoFeB/(011)-PMN-PT multiferroic heterostructure, the electric-field-controlled modulation ratios of the magnetic coercivity HC and saturation magnetic field HS can reach as high as +162% and +393%, respectively. Moreover, the electric-field-controlled magnetic coercive field HC exhibits a butterfly shape when plotted versus the applied electric fields in both modes, which matches the in-plane butterfly strain loop of the ferroelectric PMN-PT substrate. However, the electric-field-controlled saturation magnetic field HS presents a square loop, which is very consistent with the ferroelectric loop of the PMN-PT substrate. This result may be ascribed to the distinct pathway of the ferroelastic domain switching in the (011)-oriented PMN-PT substrate. This study provides a new idea for the design of spintronic devices based on multiferroic heterostructures.
Spin-Momentum Locking Induced Anisotropic Magnetoresistance in Monolayer WTe2
Publisher: American Chemical Society (ACS)
Date: 25-10-2021
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ARC Centre Of Excellence - Future Low -energy Electronics Technologies
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