Related papers: Unexpected type-II multiferroic phase in GdMnO3 un…
Due of its polymorphism, Mn$_2$FeSbO$_6$ can be synthesized at high pressures and temperatures as a ferrimagnetic ilmenite or an antiferromagnetic perovskite. The structural phase transformation is discussed in detail, and magnetic…
Multiferroic perovskites that exhibit room temperature magnetization and polarization have immense potential in the next generation of magneto-electric and spintronic memory devices. In this work, the magnetic and ferroelectric properties…
We investigate the spin-induced polarization in the multiferroic compound Ba2CuGe2O7 using variarional and finite temperature mean field approaches. The compound is described by a spin-3/2 Heisenberg model extended with easy plane…
We report a theoretical study of the non-linear magnetoelectric response of GdFeO$_3$ through an analytical approach combined with a Heisenberg model which is fitted against first-principles calculations. Our theory reproduces the…
The magnetoelectric behavior of BiFeO$_3$ has been explored on the basis of accurate density functional calculations. The structural, electronic, magnetic, and ferroelectric properties of BiFeO$_3$ are predicted correctly without including…
The origin of the spiral spin-order in perovskite multiferroic manganites $R$MnO$_{3}$ ($RE=$ Tb or Dy) is here investigated using a two $e_{\rm g}$-orbitals double-exchange model. Our main result is that the experimentally observed spiral…
In this proceeding, recent theoretical investigations by the authors on the multiferroic $R$MnO$_3$ perovskites are briefly reviewed at first. Using the double-exchange model, the realistic spiral spin order in undoped manganites such as…
Due to the strong coupling between magnetism and ferroelectricity, $(\mathrm{ND}_4)_2\mathrm{FeCl}_5\cdot\mathrm{D}_2\mathrm{O}$ exhibits several intriguing magnetic and electric phases. In this letter, we include high-order onsite spin…
Type-II multiferroics, where spin order induces ferroelectricity, exhibit strong magnetoelectric coupling. However, for the typical 2D type-II multiferroic NiI$_2$, the underlying magnetoelectric mechanism remains unclear. Here, applying…
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…
Structural, magnetic and ferromagnetic resonance characterization studies have been performed on lay-ered ferromagnetic-ferroelectric oxides that show strong magnetoelectric coupling. The samples contained thick films of ferrites or…
By means of magnetic, specific heat and pyroelectric measurements, we report on magnetic ferroelectricity in the quadruple perovskite \namno, characterized by a canted antiferromagnetic (AFM) CE structure. Surprisingly, ferroelectricity is…
First-principles density-functional calculations reveal a large spin-phonon coupling in cubic SrMnO$_{3}$, with ferromagnetic ordering producing a polar instability. Through combination of this coupling with the strain-polarization coupling…
Magnetic phase transitions in multiferroic bismuth ferrite (BiFeO3) induced by magnetic field, epitaxial strain, and composition modification are considered. These transitions from a spatially modulated spin spiral state to a homogenous…
All-electrical control of a dynamic magnetoelectric effect is demonstrated in a classical multiferroic manganite DyMnO3, a material containing coupled antiferromagnetic and ferroelectric orders. Due to intrinsic magnetoelectric coupling…
(NH$_4$)$_2$[FeCl$_5$(H$_2$O)], a member of the family of antiferromagnetic $A_2$[Fe$X_5$(H$_2$O)] compounds ($X$ = halide ion, $A$ = alkali metal or ammonium ion) is classified as a new multiferroic material. We report the onset of…
The crystallographic and magnetic phase diagram of the n=2 layered manganite La2-2xSr1+2xMn2O7 in the region x=>0.5 has been studied using temperature dependent neutron powder diffraction. The magnetic phase diagram reveals a progression of…
We performed magnetic and ferroelectric measurements, associated with Landau theory and symmetry analysis, in order to clarify the situation of the YMnO3 system, a classical example of type I multiferroics. We found that the only magnetic…
We have performed dielectric measurements and neutron diffraction experiments on the double perovskite In2NiMnO6. A ferroelectric polarization, P ~ 30 {\mu}C/m2, is observed in a polycrystalline sample below TN = 26 K where a magnetic phase…
We present a study of the dielectric, structural, and magnetic properties of the multiferroic or linear magnetoelectric substitution series [(NH$_4$)$_{1-x}$K$_x$]$_2$[FeCl$_5$(H$_2$O)]. Pyroelectric currents, magnetic susceptibilities, and…