ORCID Profile
0000-0003-1785-0864
Current Organisation
Westfälische Wilhelms-Universität Münster
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Publisher: American Chemical Society (ACS)
Date: 03-2019
DOI: 10.1021/JACS.9B00574
Abstract: Nanolaminated materials are important because of their exceptional properties and wide range of applications. Here, we demonstrate a general approach to synthesizing a series of Zn-based MAX phases and Cl-terminated MXenes originating from the replacement reaction between the MAX phase and the late transition-metal halides. The approach is a top-down route that enables the late transitional element atom (Zn in the present case) to occupy the A site in the pre-existing MAX phase structure. Using this replacement reaction between the Zn element from molten ZnCl
Publisher: Elsevier BV
Date: 02-2011
Publisher: Wiley
Date: 12-01-2022
Abstract: CaMnO 3 is a perovskite with attractive magnetic and thermoelectric properties. CaMnO 3 films are usually grown by pulsed laser deposition or radio frequency magnetron sputtering from ceramic targets. Herein, epitaxial growth of CaMnO 3– y (002) films on a ‐oriented LaAlO 3 substrate using pulsed direct current reactive magnetron sputtering is demonstrated, which is more suitable for industrial scale depositions. The CaMnO 3– y shows growth with a small in‐plane tilt of ≈0.2° toward the (200) plane of CaMnO 3– y and the () with respect to the LaAlO 3 substrate. X‐ray photoelectron spectroscopy of the electronic core levels shows an oxygen deficiency described by CaMnO 2.58 that yields a lower Seebeck coefficient and a higher electrical resistivity when compared to stoichiometric CaMnO 3 . The LaAlO 3 substrate promotes tensile‐strained growth of single crystals. Scanning transmission electron microscopy and electron energy loss spectroscopy reveal antiphase boundaries composed of Ca on Mn sites along and , forming stacking faults.
Publisher: American Vacuum Society
Date: 11-2005
DOI: 10.1116/1.2131081
Abstract: We have synthesized Ti–Si–C nanocomposite thin films by dc magnetron sputtering from a Ti3SiC2 compound target in an Ar discharge on Si(100), Al2O3(0001), and Al substrates at temperatures from room temperature to 300°C. Electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy showed that the films consisted of nanocrystalline (nc-) TiC and amorphous (a-) SiC, with the possible presence of a small amount of noncarbidic C. The growth mode was columnar, yielding a nodular film-surface morphology. Mechanically, the films exhibited a remarkable ductile behavior. Their nanoindentation hardness and E-modulus values were 20 and 290GPa, respectively. The electrical resistivity was 330μΩcm for optimal Ar pressure (4mTorr) and substrate temperature (300°C). The resulting nc-TiC∕a-SiC films performed well as electrical contact material. These films’ electrical-contact resistance against Ag was remarkably low, 6μΩ at a contact force of 800N compared to 3.2μΩ for Ag against Ag. The chemical stability of the nc-TiC∕a-SiC films was excellent, as shown by a Battelle flowing mixed corrosive-gas test, with no N, Cl, or S contaminants entering the bulk of the films.
Publisher: Informa UK Limited
Date: 10-2019
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7NR03663A
Abstract: Au-containing nanolaminated carbides Mo 2 AuC and Mo 2 (Au 1−x Ga x ) 2 C were synthesized by a thermally induced substitutional reaction in Mo 2 GaC and Mo 2 Ga 2 C, respectively.
Publisher: Elsevier BV
Date: 2010
Publisher: American Chemical Society (ACS)
Date: 08-01-2021
Publisher: American Physical Society (APS)
Date: 24-01-2022
Publisher: Wiley
Date: 06-2009
Publisher: Wiley
Date: 06-1987
Abstract: The mechanism of iron uptake and the changes which occur during cellular development of muscle cells were investigated using primary cultures of chick embryo breast muscle. Replicating presumptive myoblasts were examined in exponential growth and after growth had plateaued. These were compared to the terminally differentiated cell type, the myotube. All cells, regardless of the state of growth or differentiation, had specific receptors for transferrin. Presumptive myoblasts in exponential growth had more transferrin receptors (3.78 +/- 0.24 X 10(10) receptors/micrograms DNA) than when ision had ceased (1.70 +/- 0.14 X 10(10) receptors/micrograms DNA), while myotubes had 3.80 +/- 0.26 X 10(10) receptors/micrograms DNA. Iron uptake occurred by receptor-mediated endocytosis of transferrin. While iron was accumulated by the cells, apotransferrin was released in an undegraded form. There was a close correlation between the molar rates of endocytosis of transferrin and iron. Maximum rates of iron uptake were significantly higher in myotubes than in presumptive myoblasts in either exponential growth or after growth had plateaued. There were two rates of exocytosis of transferrin, implying the existence of two intracellular pathways for transferrin. These experiments demonstrate that iron uptake by muscle cells in culture occurs by receptor-mediated endocytosis of transferrin and that transferrin receptor numbers and the kinetics of transferrin and iron uptake vary with development of the cells.
Publisher: American Chemical Society (ACS)
Date: 06-04-2017
Abstract: We demonstrate fabrication of a two-dimensional Hf-containing MXene, Hf
Publisher: Wiley
Date: 12-1988
Abstract: The experiments described in this study were designed to investigate receptor-mediated endocytosis of transferrin and its role in iron uptake by cultured chick presumptive myoblasts ( iding and non- iding) and myotubes. The effects of a variety of inhibitors on the internalization of transferrin and iron were investigated and three main effects were found: (i) sulphydryl reagents and microtubular inhibitors reduced the rate of transferrin and iron internalization to similar degrees, (ii) metabolic inhibitors reduced the rate of iron uptake more than that of transferrin endocytosis, and (iii) lysosomotrophic agents almost completely abolished iron accumulation by the cells without any effect on the rate of transferrin internalization. The results suggest that metabolic energy is required not only for the endocytosis of transferrin but also for subsequent steps in the iron uptake process, and that iron release from transferrin occurs in acidified endosomes. Overall, these experiments show that all or virtually all of the iron taken up by developing muscle cells from transferrin occurs as a consequence of receptor-mediated endocytosis of the protein.
Publisher: Wiley
Date: 18-07-2022
Abstract: Solid‐state precipitation can be used to tailor material properties, ranging from ferromagnets and catalysts to mechanical strengthening and energy storage. Thermoelectric properties can be modified by precipitation to enhance phonon scattering while retaining charge‐carrier transmission. Here, unconventional Janus‐type nanoprecipitates are uncovered in Mg 3 Sb 1.5 Bi 0.5 formed by side‐by‐side Bi‐ and Ge‐rich appendages, in contrast to separate nanoprecipitate formation. These Janus nanoprecipitates result from local comelting of Bi and Ge during sintering, enabling an amorphous‐like lattice thermal conductivity. A precipitate size effect on phonon scattering is observed due to the balance between alloy‐disorder and nanoprecipitate scattering. The thermoelectric figure‐of‐merit ZT reaches 0.6 near room temperature and 1.6 at 773 K. The Janus nanoprecipitation can be introduced into other materials and may act as a general property‐tailoring mechanism.
Publisher: American Chemical Society (ACS)
Date: 10-01-2023
Publisher: Elsevier BV
Date: 10-2014
Publisher: American Association for the Advancement of Science (AAAS)
Date: 17-03-2023
Abstract: Intercalated layered materials offer distinctive properties and serve as precursors for important two-dimensional (2D) materials. However, intercalation of non–van der Waals structures, which can expand the family of 2D materials, is difficult. We report a structural editing protocol for layered carbides (MAX phases) and their 2D derivatives (MXenes). Gap-opening and species-intercalating stages were respectively mediated by chemical scissors and intercalants, which created a large family of MAX phases with unconventional elements and structures, as well as MXenes with versatile terminals. The removal of terminals in MXenes with metal scissors and then the stitching of 2D carbide nanosheets with atom intercalation leads to the reconstruction of MAX phases and a family of metal-intercalated 2D carbides, both of which may drive advances in fields ranging from energy to printed electronics.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9RA10007E
Abstract: Reduction of thermal conductivity of sputtered CaMn 1−x Nb x O 3 thin films by secondary Ruddlesden–Popper phase and grain size optimization.
Publisher: Elsevier BV
Date: 11-2014
Publisher: Wiley
Date: 31-05-2005
DOI: 10.1111/J.1600-0838.2005.00467.X
Abstract: Mechanical force is generated within skeletal muscle cells by contraction of specialized myofibrillar proteins. This paper explores how the contractile force generated at the sarcomeres within an in idual muscle fiber is transferred through the connective tissue to move the bones. The initial key point for transfer of the contractile force is the muscle cell membrane (sarcolemma) where force is transferred laterally to the basement membrane (specialized extracellular matrix rich in laminins) to be integrated within the connective tissue (rich in collagens) before transmission to the tendons. Connections between (1) key molecules outside the myofiber in the basement membrane to (2) molecules within the sarcolemma of the myofiber and (3) the internal cytoplasmic structures of the cytoskeleton and sarcomeres are evaluated. Disturbances to many components of this complex interactive system adversely affect skeletal muscle strength and integrity, and can result in severe muscle diseases. The mechanical aspects of these crucial linkages are discussed, with particular reference to defects in laminin-alpha2 and integrin-alpha7. Novel interventions to potentially increase muscle strength and reduce myofiber damage are mentioned, and these are also highly relevant to muscle diseases and aging muscle.
Publisher: Elsevier BV
Date: 05-2006
Publisher: Springer Science and Business Media LLC
Date: 13-04-2020
Publisher: Springer Science and Business Media LLC
Date: 18-01-2021
Publisher: American Chemical Society (ACS)
Date: 30-05-2018
Publisher: American Chemical Society (ACS)
Date: 04-02-2019
Abstract: Two-dimensional (2D) materials have attracted intense attention in nanoscience and nanotechnology due to their outstanding properties. Among these materials, the emerging family of 2D transition metal carbides, carbonitrides, and nitrides (referred to as MXenes) stands out because of the vast available chemical space for tuning materials chemistry and surface termination, offering opportunities for property tailoring. Specifically, semiconducting properties are needed to enable utilization in optoelectronics, but direct band gaps are experimentally challenging to achieve in these 2D carbides. Here, we demonstrate the fabrication of 2D hydroxyl-functionalized and carbon-deficient scandium carbide, namely, ScC
Publisher: AIP Publishing
Date: 08-2009
DOI: 10.1063/1.3155800
Abstract: Highly textured FeSb2 films were produced on quartz wafers by a sputtering method. Their resistivity and Seebeck coefficient (S) were measured and a maximum absolute value of S∼160 μV K−1 at 50 K was obtained. Hall measurements were employed to study the charge carrier concentrations and Hall mobilities of the FeSb2 films. By comparing with the transport properties of FeSb2 single crystals and an extrinsically doped FeSb1.98Te0.02 single crystal, the thermoelectric properties of the FeSb2 films are demonstrated to be dominated by the intrinsic properties of FeSb2 at a high charge carrier concentration.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9NA00324J
Abstract: MXenes are an extensive family of 2D transition metal carbides and nitrides, whose properties are strongly affected by surface terminations, typically O and F. Herein, we enable chlorine as a new termination, thereby expanding the property space.
Publisher: American Society for Clinical Investigation
Date: 18-05-2020
DOI: 10.1172/JCI99027
Publisher: Proceedings of the National Academy of Sciences
Date: 26-12-2019
Abstract: M n+1 AX n phases are a family of inherently nanolaminated ternary compounds with hexagonal crystal structure (space group P 63 /mmc , 194 ). Here, M is vanadium element, and A is Fe, Co, Ni, Mn, or their binary/ternary/quaternary mixtures. Due to the elemental flexibility at A site, 15 nanolaminated V 2 ( A x Sn 1-x )C MAX phases are synthesized, including 1 high-entropy MAX phase that all Fe, Co, Ni, Mn, and Sn elements simultaneously occupied A site. Tailoring of in idual single–atom-thick layers in nanolaminated MAX phases offers atomic-level control of material properties, such as their distinct magnetic behaviors. The alloying in 2-dimensional A layer of MAX phases provides a unique route to design their crystal structure and to discover unexploited properties, which would develop promising functional materials for microelectronic device.
Publisher: American Chemical Society (ACS)
Date: 22-07-2019
Abstract: A Ti
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8RA07270A
Abstract: Ti 3 C 2 T x (MXene) thin film shows elimination of –F and domination of –O surface terminations after NaOH treatment followed by annealing while preserving the electrical conductivity of the film.
Publisher: Elsevier BV
Date: 03-2012
Publisher: American Physical Society (APS)
Date: 05-05-2023
Publisher: IOP Publishing
Date: 14-02-2017
Abstract: Inherently and artificially layered materials are commonly investigated both for fundamental scientific purposes and for technological application. When a layered material is thinned or delaminated to its physical limits, a two-dimensional (2D) material is formed and exhibits novel properties compared to its bulk parent phase. The complex layered phases known as ‘MAX phases’ (where M = early transition metal, A = A-group element, e.g. Al or Si, and X = C or N) are an exciting model system for materials design and the understanding of process-structure-property relationships. When the A layers are selectively etched from the MAX phases, a new type of 2D material is formed, named MXene to emphasize the relation to the MAX phases and the parallel with graphene. Since their discovery in 2011, MXenes have rapidly become established as a novel class of 2D materials with remarkable possibilities for composition variations and property tuning. This article gives a brief overview of MAX phases and MXene from a thin-film perspective, reviewing theory, characterization by electron microscopy, properties and how these are affected by the change in dimensionality, and outstanding challenges.
Publisher: Springer Science and Business Media LLC
Date: 26-10-2014
Publisher: IOP Publishing
Date: 20-02-2019
Publisher: IEEE
Date: 2005
Publisher: Elsevier BV
Date: 02-2007
Publisher: AIP Publishing
Date: 09-2021
DOI: 10.1063/5.0059078
Abstract: Mn+1AXn (MAX) phases' nanolaminated ternary carbides or nitrides possess a unique crystal structure in which single-atom-thick “A” sublayers are interleaved by alternative stacking of a “Mn+1Xn” sublayer these materials have been investigated as promising high-safety structural materials for industrial applications because of their laminated structure and metal and ceramic properties. However, limited of A-site elements in the definition of Mn+1AXn phases, it is a huge challenge for designing nanolaminated ferromagnetic materials with single-atom-thick two-dimensional iron layers occupying the A layers in the Mn+1AXn phases. Here, we report three new ternary magnetic Mn+1AXn phases (Ta2FeC, Ti2FeN, and Nb2FeC) with A sublayers of single-atom-thick two-dimensional iron through an isomorphous replacement reaction of Mn+1AXn precursors (Ta2AlC, Ti2AlN, and Nb2AlC) with a Lewis acid salts (FeCl2). All these Mn+1AXn phases exhibit ferromagnetic behavior. The Curie temperatures of the Ta2FeC and Nb2FeC Mn+1AXn phases are 281 and 291 K, respectively, i.e., close to room temperature. The saturation magnetization of these ternary magnetic MAX phases is almost two orders of magnitude higher than V2(Sn,Fe)C, whose A-site is partially substituted by Fe. Theoretical calculations on magnetic orderings of spin moments of Fe atoms in these nanolaminated magnetic Mn+1AXn phases reveal that the magnetism can be mainly ascribed to an intralayer exchange interaction of the two-dimensional Fe atomic layers. Owing to the richness in composition of Mn+1AXn phases, our work provides a large imaginary space for constructing functional single-atom-thick two-dimensional layers in materials using these nanolaminated templates.
Publisher: American Chemical Society (ACS)
Date: 31-03-2023
No related grants have been discovered for Per Eklund.