Related papers: Oxygen vacancies induced ferroelectricity in relax…
In this work we study the stabilization of the orthorhombic phases in small Hf0.5Zr0.5O2 nanoparticles (average size ~ 7 nm) annealed under different oxygen partial pressures. Concentration of the oxygen vacancies, which is determined by…
A first-principles-based model is developed to investigate the influence of lead vacancies on the properties of relaxor ferroelectric Pb(Sc1/2Nb1/2)O3 (PSN). Lead vacancies generate large, inhomogeneous, electric fields that reduce barriers…
We use first-principles calculations based on density functional theory to investigate the interplay between oxygen vacancies, A-site cation size / tolerance factor, epitaxial strain, ferroelectricity and magnetism in the perovskite…
Enhanced conductivity at ferroelectric domain walls in BiFeO$_3$ has been widely observed, yet the microscopic origins of this effect, including electronic contributions from domain-wall defects, are incompletely understood at the atomistic…
{\it Ab initio} calculations within density functional theory with generalized gradient approximation have been performed to study the effects of oxygen vacancies on the electronic structure and magnetism in undoped V$_2$O$_{5-x}$ ($0 < x <…
The discovery of ferroelectric HfO2 in thin films and more recently in bulk is an important breakthrough because of its silicon-compatibility and unexpectedly persistent polarization at low dimensions, but the origin of its ferroelectricity…
Controlling functionalities, such as magnetism or ferroelectricity, by means of oxygen vacancies (VO) is a key issue for the future development of transition metal oxides. Progress in this field is currently addressed through VO variations…
Defects such as oxygen vacancy are widely considered to be critical for the performance of HfO2-based devices, and yet atomistic mechanisms underlying various exotic effects such as wake-up and fluid imprint remain elusive. Here, guided by…
Relaxor ferrolectrics are important in technological applications due to a strong electromechanical response, energy storage capacity, electrocaloric effect, and pyroelectric energy conversion properties. Current efforts to discover and…
The defect stability in a prototypical perovskite oxide superlattice consisting of SrTiO$_3$ and PbTiO$_3$ (STO/PTO) is determined using first principles density functional theory calculations. Specifically, the oxygen vacancy formation…
We propose a model with few parameters, for vacancy-induced ferromagnetism based on a correlated model for anions (oxygen orbitals) with random potentials that represent cation vacancies. There is a range of potential strength for which…
We have measured the bending-induced polarization of Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals with compositions at the relaxor-ferroelectric phase boundary. The crystals display very large flexoelectricity, with flexocoupling coefficients an…
Relaxor ferroelectric PbMg_1/3Ta_2/3O_3 ceramics and thin films were investigated by means of broad-band dielectric, time-domain terahertz (THz) and Fourier-transform infrared (IR) spectroscopy in the frequency range 100 Hz - 90 THz at…
Using first-principles calculations, we predict that tunable ferroelectricity can be realized in oxide perovskites with the Grenier structure and ordered oxygen vacancies. Specifically, we show that $R_{1/3}A_{2/3}\mathrm{FeO}_{2.67}$…
Thermodynamic, structural and electronic properties of isolated copper and iron atoms as well as their complexes with oxygen vacancies in tetragonal lead titanate are investigated by means of first principles calculations. Both dopants…
We discovered a near room temperature lead-free relaxor-ferroelectric (Ba0.6Bi0.2Li0.2)TiO3 (BBLT) having A-site compositional disordered ABO3 perovskite structure. Microstructure-property relations revealed that the chemical…
\indent It is a generally accepted fact that the unique dielectric properties of relaxor ferroelectrics are related to the formation of polar nanoregion (PNRs). Less well recognized is the corollary that, because they are polar and…
The dielectric response in relaxor ferroelectrics is analyzed in the framework a model for the polarization dynamics in the presence of polar clusters. We associate the origin of polar clusters with the atoms displaced from their…
Oxygen vacancy ordering in perovskite-type transition-metal oxides plays an important role in the emergence of exotic electronic properties, as typified by superconducting cuprates. In this study, we predict the stability of…
Relaxor ferroelectrics exhibit exceptional dielectric and electromechanical properties, yet their microscopic origins remain elusive due to the interplay of hierarchical polar structures and chemical complexity. While models based on polar…