Related papers: Antiferroelectric negative capacitance from a stru…
We study the interplay of structural and polar distortions in hexagonal YMnO3 and short-period PbTiO3/SrTiO3 superlattices by means of first-principles calculations at constrained electric displacement field D. We find that in YMnO3 the…
The ferroelectric switching speed has been experimentally obfuscated by the interaction between the measurement circuit and the ferroelectric switching itself. This has prohibited the observation of real material responses at nanosecond…
We demonstrate that small but finite ferroelectric polarization ($\sim$0.01 $\mu$C/cm$^2$) emerges in orthorhombic LuFeO$_3$ ($Pnma$) at $T_N$ ($\sim$600 K) because of commensurate (k = 0) and collinear magnetic structure. The synchrotron…
The appearance of spontaneous polarization in CuInP$_{2}$S$_{6}$ ferrielectrics is related to the second order Jahn-Teller effect for copper cations located in a double-well local potential, the stereoactivity of indium cations located in a…
We consider nanoflakes of van der Waals ferrielectric CuInP$_2$S$_6$ covered by an ionic surface charge and reveal the appearance of polar states with relatively high polarization ~5 microC/cm$^2$ and stored free charge ~10 microC/cm$%2$,…
In the paper we consider size effects of phase transitions and polar properties of the thin antiferroelectric films. We modified phenomenological approach proposed by Kittel. The Euler-Lagrange equations were solved by direct variational…
Motivated by the recently discovered superconductivity in Sr-doped nickelate oxides NdNiO$_2$, we predict a material BiNiO$_2$ that provides an opportunity to study the intertwined ferroelectricity, metallicity, and magnetism in a crystal…
Magnetoelectric coupling in the polycrystalline antiferromagnets CuFe0.95Rh0.05O2 and CuFeO2 has been investigated. For both samples, electric polarization was observed in the absence of an applied external magnetic field demonstrating that…
My research is dedicated to the electronic properties of functional oxides. My activity specifically focuses on ferroelectric tunnel junctions in which an ultrathin layer of ferroelectric material is intercalated between two metallic…
The precise crystal symmetry and hence the emergence of the electric polarization still remains an open question in the multiferroic materials $R$Mn$_2$O$_5$ ($R$ = rare-earth, Bi, Y). While previous diffraction studies have indicated that…
We formulate a general theory of the dielectric response of a lattice with a structural transition and a polarization instability due to a soft-optic mode coupled to low energy electronic excitations by the electromagnetic fields. the…
We study the multiferroic properties in the distorted tetrahedral quasi-one dimensional spin system Cu$_3$Mo$_2$O$_9$, in which the effects of the low dimensionality and the magnetic frustration are expected to appear simultaneously. We…
High-frequency dielectric studies of Bi_0.85Nd_0.15FeO_3 ceramics performed betweeen 100 and 900 K reveal hardening of most polar phonons on cooling below antiferroelectric phase transition, which occurs near 600 K. Moreover, a strong THz…
Vertical ferroelectricity where a net dipole moment appears as a result of in-plane ionic displacements has gained enormous attention following its discovery in transition metal dichalcogenides. Based on first-principles calculations, we…
Ferroelectricity is observed in orthorhombic $HoMnO_3$ and $YMnO_3$ at the magnetic lock-in transitions into an E-type structure or an incommensurate phase with a temperature independent wave vector, respectively. In $HoMnO_3$ the…
Charge-order-driven ferroelectrics are an emerging class of functional materials, distinct from conventional ferroelectrics, where electron-dominated switching can occur at high frequency. Despite their promise, only a few systems…
We have studied the electrocaloric response of the archetypal antiferroelectric PbZrO3 as a function of voltage and temperature in the vicinity of its antiferroelectric-paraelectric phase transition. Large electrocaloric effects of opposite…
Material surfaces encompass structural and chemical discontinuities that often lead to the loss of the property of interest in the so-called dead layers. It is notably problematic in nanoscale oxide electronics, where the integration of…
In hybrid improper ferroelectric systems, polarization arises from the onset of successive nonpolar lattice modes. In this work, measurements and modeling were performed to determine the spatial symmetries of the phases involved in the…
We report ferrielectricity in a single-phase crystal, TSCC -- tris-sarcosine calcium chloride [(CH3NHCH2COOH)3CaCl2]. Ferrielectricity is well known in smectic liquid crystals but almost unknown in true crystalline solids. Pulvari reported…