9 research outputs found
Reversible Control of Magnetic Interactions by Electric Field in a Single Phase Material
Intrinsic magnetoelectric coupling describes the interaction between magnetic
and electric polarization through an inherent microscopic mechanism in a single
phase material. This phenomenon has the potential to control the magnetic state
of a material with an electric field, an enticing prospect for device
engineering. We demonstrate 'giant' magnetoelectric cross-field control in a
single phase rare earth titanate film. In bulk form, EuTiO3 is
antiferromagnetic. However, both anti and ferromagnetic interactions coexist
between different nearest neighbor europium ions. In thin epitaxial films,
strain can be used to alter the relative strength of the magnetic exchange
constants. Here, we not only show that moderate biaxial compression
precipitates local magnetic competition, but also demonstrate that the
application of an electric field at this strain state, switches the magnetic
ground state. Using first principles density functional theory, we resolve the
underlying microscopic mechanism resulting in the EuTiO3 G-type magnetic
structure and illustrate how it is responsible for the 'giant' cross-field
magnetoelectric effect
Influence of pressure on the structural, dynamical, and electronic properties of the SnP2S6 layered crystal
International audienceUsing the density functional theory in the local density approximation the pressure dependence of the structural, dynamical, and electronic properties of the SnP2S6 layered semiconductor in the pressure range up to 35 GPa is investigated. The pressure dependence of the lattice parameters is well described by the Murnaghan equation of state. The nonmonotonic pressure dependence of the structural polarization is obtained. The SnP2S6 compound is predicted to be an indirect-gap semiconductor. At a pressure of above 10 GPa, an indirect-direct bandgap crossover is observed. The pressure dependence of the long-wavelength lattice vibration frequencies is calculated and compared with experimental results from Raman spectroscopy in the pressure range 0–21.5 GPa. Full phonon dispersion curves do not indicate mode softening over the entire range of the Brillouin zone. The stability of the structure under pressure is discussed