Related papers: First-principles study of improper ferroelectricit…
Terahertz electromagnetic excitations in the multiferroic TbMnO3 at the field-induced magnetic transition are investigated for different orientations of the magnetic cycloid. In addition to the electromagnon along the a-axis, the detailed…
The magnetic-field-induced 90-degree flop of ferroelectric polarization P in a spin-spiral multiferroic material TbMnO3 is theoretically studied based on a microscopic spin model. We find that the direction of the P-flop or the choice of…
The electronic valence state of Mn in Pb(Zr0.2Ti0.8)O3/La0.8Sr0.2MnO3 multiferroic heterostructures is probed by near edge x-ray absorption spectroscopy as a function of the ferroelectric polarization. We observe a temperature independent…
We investigate the origin of the coplanar helicoidal magnetic structure and the ferroelectric polarization in Cu3Nb2O8 by combining first-principles calculations and our spin-induced ferroelectric polarization model. The coplanar helicoidal…
Non-resonant X-ray magnetic scattering has been used to study the magnetic structure of multiferroic TbMnO3 in its ferroelectric phase. Circularly polarized X-rays were combined with a full polarization analysis of the scattered beam to…
Ferroelectricity has been found to occur in several insulating systems, such as TbMnO$_3$ (TMO) and Ni$_3$V$_2$O$_8$ (NVO) which have more than one phase with incommensurately modulated long-range magnetic order. Here we give a…
The ferroelectric polarization of triangular-lattice antiferromagnets induced by helical spin-spiral order is not explained by any existing model of magnetic-order-driven ferroelectricity. We resolve this problem by developing a general…
Using first principle calculations under the framework of density functional theory we have investigated the electronic structure, magnetism and ferroelectric polarization in the triangular lattice antiferromagnet AgFeO2, and its comparison…
Magneto-electric multiferroics exemplified by TbMnO3 possess both magnetic and ferroelectric long-range order. The magnetic order is mostly understood, whereas the nature of the ferroelectricity has remained more elusive. Competing models…
The compound Ba3HoRu2O9 magnetically orders at 50 K (TN1) followed by another complex magnetic ordering at 10.2 K (TN2). The 2nd magnetic phase transition was characterized by the co-existence of two competing magnetic ground states…
Motivated by recent terahertz (THz) spectroscopy measurements in $\alpha$-RuCl$_3$, we develop a theory for magnetoelectric (ME) effects in Mott insulators of $d^5$ transition metal ions in an octahedral crystal field. For $4d$ and $5d$…
We report the direct measurement of antiferromagnetic spin polarization at the oxygen sites in the multiferroic TbMn2O5, through resonant soft x-ray magnetic scattering. This supports recent theoretical models suggesting that the oxygen…
By means of first-principles simulations, we unambiguously show that improper ferroelectricity in magnetite in the low-temperature insulating phase is driven by charge-ordering. An accurate comparison between monoclinic ferroelectric Cc and…
In contrast to conventional assumptions, we show that the Dzyaloshinskii-Moriya interaction can be of non-relativistic origin, in particular in materials with a non-collinear magnetic configuration, where non-relativistic contributions can…
The relationship between magnetic order and ferroelectric properties has been investigated for MnWO$_4$ with long-wavelength magnetic structure. Spontaneous electric polarization is observed in an elliptical spiral spin phase. The…
Spin waves in ferromagnetic materials are predominantly characterized by right-handed circular polarization due to symmetry breaking induced by net magnetization. However, magnetic interactions, including the external magnetic field,…
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…
Aiming at increasing the ferroelectric polarization in AFM-E ortho-\hmo, we investigate the in-plane strain effects on both the magnetic configuration and the polarization by means of density functional theory calculations and model…
Piezo-magnetoelectric effect, namely simultaneous induction of both the ferromagnetic moment and electric polarization by an application of uniaxial stress, was achieved in the non-ferroelectric and antiferromagnetic ground state of…
The influence of the spin-orbit coupling on the magnetic structure of deposited transition metal nanostructure systems has been studied by fully relativistic electronic structure calculations. The interplay of exchange coupling and magnetic…