Phys.org December 5, 2024 Strong coupling between polarization (P) and strain (ɛ) in ferroelectric complex oxides offers unique opportunities to dramatically tune their properties. An international team of researchers (USA – Pennsylvania State University, Cornell University, Stanford University, University of Nebraska, Argonne National Laboratory, Belgium, Germany) demonstrated strain tuning of ferroelectricity in epitaxial potassium niobate (KNbO3) thin films grown by sub-oxide molecular beam epitaxy. While bulk KNbO3 exhibited three ferroelectric transitions and a Curie temperature (Tc) of ≈676 K, phase-field modeling predicted that a biaxial strain pushes its Tc > 975 K, its decomposition temperature in air, and for −1.4% […]
Tag Archives: ferroelectricity
From a five-layer graphene sandwich, a rare electronic state emerges
Science Daily October 18, 2023 Multiferroics have multifunctional electrical and magnetic device applications. Two-dimensional materials with honeycomb lattices offer opportunities to engineer unconventional multiferroicity. Orbital multiferroics could offer strong valley–magnetic couplings and large responses to external fields—enabling device applications such as multiple-state memory elements and electric control of the valley and magnetic states. An international team of researchers (USA – MIT, Harvard University, Japan) has shown orbital multiferroicity in Penta layer rhombohedral graphene. They observed anomalous Hall signals Rxy with an exceptionally large Hall angle and orbital magnetic hysteresis at hole doping. There were four such states with different valley […]
Scientists uncover mystery of important material for semiconductors at the surface
Nanowerk September 16, 2023 Ferroelectricity in binary oxides including hafnia and zirconia is interesting because of their unconventional physical mechanisms and the potential for the integration of these materials into semiconductor workflows. Behaviors such as wake-up phenomena and an extreme sensitivity to electrode and processing conditions suggest that ferroelectricity in these materials is strongly influenced by other factors, including electrochemical boundary conditions and strain. An international team of researchers (USA – Oak Ridge National Laboratory, University of Virginia, Charlottesville, Carnegie Mellon University, University of Tennessee, Knoxville, Ukraine) argued that the properties of these materials emerge due to the interplay between […]
New electronic phenomenon discovered
Science Daily August 11, 2021 A team of researchers in the US (University of North Florida, University of Illinois, Arizona State University) has demonstrated a new electronic phenomenon they call “asymmetric ferroelectricity” in atomic layer superlattices constructed using three constituent phases, CaTiO3, SrTiO3 and BaTiO3. The stacking sequence of the atomic layers is found to control the symmetry of the high-temperature dielectric response. When a nanostructured asymmetric strain is programmed into the lattice via the stacking order, the natural symmetry at high temperatures is removed and a polarized sample is obtained in which the polarization increases as the temperature is […]