Switchable topological polar states in epitaxial BaTiO nanoislands on silicon.

A fascinating aspect of nanoscale ferroelectric materials is the emergence of topological polar textures, which include various complex and stable polarization configurations. The manipulation of such topological textures through external stimuli like electric fields holds promise for advanced nanoelectronics applications. There are, however, several challenges to reach potential applications, among which reliably creating and controlling these textures at the nanoscale on silicon, and with lead-free compounds.

Thermally Stable Capacitive Energy-Density and Colossal Electrocaloric and Pyroelectric Effects of Sm-Doped Pb(MgNb)O-PbTiO Thin Films.

Sm-doped Pb(MgNb)O-PbTiO (Sm-PMN-PT) bulk materials have revealed outstanding ferroelectric and piezoelectric properties due to enhanced local structural heterogeneity. In this study, we further explore the potential of Sm-PMN-PT by fabricating epitaxial thin films by pulsed laser deposition, revealing that Sm doping significantly improves the capacitive energy-storage, piezoelectric, electrocaloric, and pyroelectric properties of PMN-PT thin films. These Sm-PMN-PT thin films exhibit fatigue-free performance up to 10 charge-discharge cycles and maintain thermal stability across a wide temperature range from -40 to 200 °C.

Polarization Topology at the Nominally Charged Domain Walls in Uniaxial Ferroelectrics.

Ferroelectric domain walls provide a fertile environment for novel materials physics. If a polarization discontinuity arises, it can drive a redistribution of electronic carriers and changes in band structure, which often result in emergent 2D conductivity. If such a discontinuity is not tolerated, then its amelioration usually involves the formation of complex topological patterns, such as flux-closure domains, dipolar vortices, skyrmions, merons, or Hopfions.

Thermal-stability of the enhanced piezoelectric, energy storage and electrocaloric properties of a lead-free BCZT ceramic.

The lead-free BaCaZrTiO (BCZT) relaxor ferroelectric ceramic has aroused much attention due to its enhanced piezoelectric, energy storage and electrocaloric properties. In this study, the BCZT ceramic was elaborated by the solid-state reaction route, and the temperature-dependence of the structural, electrical, piezoelectric, energy storage and electrocaloric properties was investigated. X-ray diffraction analysis revealed a pure perovskite phase, and the temperature-dependence of Raman spectroscopy, dielectric and ferroelectric measurements revealed the phase transitions in the BCZT ceramic.

Design of lead-free BCZT-based ceramics with enhanced piezoelectric energy harvesting performances.

The design of lead-free ceramics for piezoelectric energy harvesting applications has become a hot topic. Among these materials, BaCaZrTiO (BCZT) and BaTiSnO (BTSn) are considered as potential candidates due to their enhanced piezoelectric properties. Here, the structural, electrical, piezoelectric and piezoelectric energy harvesting properties of the (1 - )BaCaZrTiO-BaTiSnO (BTSn, = 0.

Temperature Dependence of Dielectric Properties of Ferroelectric Heterostructures with Domain-Provided Negative Capacitance.

It is well known that the ferroelectric layers in dielectric/ferroelectric/dielectric heterostructures harbor polarization domains resulting in the negative capacitance crucial for manufacturing energy-efficient field-effect transistors. However, the temperature behavior of the characteristic dielectric properties, and, hence, the corresponding behavior of the negative capacitance, are still poorly understood, restraining the technological progress thereof. Here we investigate the temperature-dependent properties of domain structures in the SrTiO/PbTiO/SrTiO heterostructures and demonstrate that the temperature-thickness phase diagram of the system includes the ferroelectric and paraelectric regions, which exhibit different responses to the applied electric field.

Tunable Electromechanical Properties of a Barium Strontium Titanate Ferroelectric Film Under a Uniaxial Stress.

The possibility of the development of MEMS devices based on the tunable ferroelectric film Ba Sr O properties under uniaxial deformation was studied theoretically. The thermodynamic model of the phase transitions for the film under uniaxial stress was constructed. The behavior of the material constants for the film in various phase states was investigated.

Controllable skyrmion chirality in ferroelectrics.

Chirality, an intrinsic handedness, is one of the most intriguing fundamental phenomena in nature. Materials composed of chiral molecules find broad applications in areas ranging from nonlinear optics and spintronics to biology and pharmaceuticals. However, chirality is usually an invariable inherent property of a given material that cannot be easily changed at will.

Hopfions emerge in ferroelectrics.

Paradigmatic knotted solitons, Hopfions, that are characterized by topological Hopf invariant, attract an intense attention in the diverse areas of physics ranging from high-energy physics, cosmology and astrophysics to biology, magneto- and hydrodynamics and condensed matter physics. Yet, while being of broad interest, they remain elusive and under-explored. Here we demonstrate that Hopfions emerge as a basic configuration of polarization field in confined ferroelectric nanoparticles.

Tunable pyroelectric properties of barium strontium titanate thin films.

We studied the influence of the induced strain and applied electric field on the ground state of ferroelectric BaSrTiO thin films, deposited on the cubic (0 0 1) substrate. The dependence of the pyroelectric coefficient on the applied field is calculated for the different values of the induced strain. We found that tuning of the misfit strain in the film under the dielectric bolometer mode by the proper selection of substrate makes it possible to create the structures with very large values of the pyroelectric coefficient.