55 research outputs found
Ferroelectrically induced weak-ferromagnetism in a single-phase multiferroic by design
We present a strategy to design structures for which a polar lattice
distortion induces weak ferromagnetism. We identify a large class of
multiferroic oxides as potential realizations and use density-functional theory
to screen several promising candidates. By elucidating the interplay between
the polarization and the Dzyaloshinskii-Moriya vector, we show how the
direction of the magnetization can be switched between 180 symmetry
equivalent states with an applied electric field.Comment: Significantly revised for clarit
Spin-Filtering Multiferroic-Semiconductor Heterojunctions
We report on the structural and electronic properties of the interface
between the multiferoic oxide YMnO and wide band-gap semiconductor GaN
studied with the Hubbard-corrected local spin density approximation (LSDA+U) to
density-functional theory (DFT). We find that the band offsets at the interface
between antiferromagnetically ordered YMnO and GaN are different for
spin-up and spin-down states. This behavior is due to the spin splitting of the
valence band induced by the interface. The energy barrier depends on the
relative orientation of the electric polarization with respect to the
polarization direction of the GaN substrate suggesting an opportunity to create
magnetic tunnel junctions in this materials system.Comment: 4 pages, 4 figure
Magnetic-induced phonon anisotropy in ZnCrO from first principles
We have studied the influence of magnetic order on the optical phonons of the
geometrically frustrated spinel ZnCrO from first-principles. By mapping
the first-principles phonon calculations onto a Heisenberg-like model, we
developed a method to calculate exchange derivatives and subsequently the
spin-phonon couping parameter from first-principles. All calculations were
performed within LSDA+U
Magnetic and electric phase control in epitaxial EuTiO from first principles
We propose a design strategy - based on the coupling of spins, optical
phonons, and strain - for systems in which magnetic (electric) phase control
can be achieved by an applied electric (magnetic) field. Using first-principles
density-functional theory calculations, we present a realization of this
strategy for the magnetic perovskite EuTiO.Comment: Significantly revised for clarit
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