ORCID Profile
0000-0003-3432-7610
Current Organisations
University of Aveiro
,
Helmholtz Centre for Environmental Research - UFZ
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Springer Science and Business Media LLC
Date: 21-01-2016
DOI: 10.1038/SREP19630
Abstract: Electromechanical properties such as d 33 and strain are significantly enhanced at morphotropic phase boundaries (MPBs) between two or more different crystal structures. Many actuators, sensors and MEMS devices are therefore systems with MPBs, usually between polar phases in lead (Pb)-based ferroelectric ceramics. In the search for Pb-free alternatives, systems with MPBs between polar and non-polar phases have recently been theorized as having great promise. While such an MPB was identified in rare-earth (RE) modified bismuth ferrite (BFO) thin films, synthesis challenges have prevented its realization in ceramics. Overcoming these, we demonstrate a comparable electromechanical response to Pb-based materials at the polar-to-non-polar MPB in Sm modified BFO. This arises from ‘dual’ strain mechanisms: ferroelectric/ferroelastic switching and a previously unreported electric-field induced transition of an anti-polar intermediate phase. We show that intermediate phases play an important role in the macroscopic strain response and may have potential to enhance electromechanical properties at polar-to-non-polar MPBs.
Publisher: Informa UK Limited
Date: 06-2003
Publisher: AIP Publishing
Date: 30-07-2001
DOI: 10.1063/1.1386616
Abstract: Ferroelectric materials with Bi-layered structure such as SrBi2Ta2O9 and SrBi2Nb2O9 are now intensively investigated in view of their applications in nonvolatile computer memories and high-temperature piezoelectric transducers. When Sr2+ is substituted with Ba2+, a significant disorder is induced and the material exhibits broadening of the phase transition. Such broadening is essential for applications since it allows achieving smooth temperature characteristics while maintaining high dielectric and piezoelectric properties. In this work, stoichiometric dense BaBi2Nb2O9 (BBN) ceramics are sintered using a mixed oxide route. Dielectric and ferroelectric properties are investigated in a broad range of temperatures and frequencies. Strong dispersion of the complex relative dielectric permittivity is observed including typical relaxor features such as shift of the permittivity maximum with frequency and broadening of the relaxation time spectrum with decreasing temperature. The dielectric relaxation obeys the Vögel–Fulcher relationship with anomalously low freezing temperature (Tf≈100 K), which is much lower than the permittivity maximum in the radio-frequency range. Polarization hysteresis loops testify linear properties of BBN at all temperatures above Tf. The properties of BBN ceramics are compared to conventional relaxor systems such as Pb(Mg, Nb)O3 and (Pb, La)(Zr, Ti)O3.
Publisher: Informa UK Limited
Date: 2001
Publisher: Springer Science and Business Media LLC
Date: 11-08-2012
Publisher: Springer International Publishing
Date: 2019
Publisher: Elsevier BV
Date: 2001
Publisher: Elsevier BV
Date: 2001
Publisher: Elsevier BV
Date: 09-2001
Publisher: Wiley
Date: 29-03-1970
Publisher: IOP Publishing
Date: 21-07-2010
DOI: 10.1088/0957-4484/21/32/325707
Abstract: We report a new method for the synthesis of photoluminescent SrAl(2)O(4):Ce(3+), Dy(3+), Eu(2+) nanotubes, PL-SNT:Ce(III), Ln, using solid-state reaction and post-annealing approach. This new optical nanotubular structure was characterized by HRTEM, SEM, AFM, EDX, steady-state and time-resolved PL spectroscopy. A series of f-f and f-d-transitions with light emission in structured bands peaking at 488 nm arising from the polymorphism of the host lattice was correlated with an intercrystalline distal-effect on the afterglow phenomenon.
Location: United States of America
Location: Russian Federation
No related grants have been discovered for Andrei Kholkin.