Journal ArticleDOI
Anisotropic Superexchange Interaction and Weak Ferromagnetism
TLDR
In this paper, the Anderson theory of superexchange was extended to include spin-orbit coupling and the antisymmetric spin coupling suggested by Dzialoshinski from purely symmetry grounds and the symmetric pseudodipolar interaction were derived.Abstract:
A theory of anisotropic superexchange interaction is developed by extending the Anderson theory of superexchange to include spin-orbit coupling. The antisymmetric spin coupling suggested by Dzialoshinski from purely symmetry grounds and the symmetric pseudodipolar interaction are derived. Their orders of magnitudes are estimated to be ($\frac{\ensuremath{\Delta}g}{g}$) and ${(\frac{\ensuremath{\Delta}g}{g})}^{2}$ times the isotropic superexchange energy, respectively. Higher order spin couplings are also discussed. As an example of antisymmetric spin coupling the case of Cu${\mathrm{Cl}}_{2}$\ifmmode\cdot\else\textperiodcentered\fi{}2${\mathrm{H}}_{2}$O is illustrated. In Cu${\mathrm{Cl}}_{2}$\ifmmode\cdot\else\textperiodcentered\fi{}2${\mathrm{H}}_{2}$O, a spin arrangement which is different from one accepted so far is proposed. This antisymmetric interaction is shown to be responsible for weak ferromagnetism in $\ensuremath{\alpha}$-${\mathrm{Fe}}_{2}$${\mathrm{O}}_{3}$, MnC${\mathrm{O}}_{3}$, and Cr${\mathrm{F}}_{3}$. The paramagnetic susceptibility perpendicular to the trigonal axis is expected to increase very sharply near the N\'eel temperature as the temperature is lowered, as was actually observed in Cr${\mathrm{F}}_{3}$.read more
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Journal ArticleDOI
Near room-temperature formation of a skyrmion crystal in thin-films of the helimagnet FeGe
Xiuzhen Yu,Naoya Kanazawa,Yoshinori Onose,Koji Kimoto,Weizhu Zhang,Shintaro Ishiwata,Yoshio Matsui,Yoshinori Tokura +7 more
TL;DR: The formation of SkX close to room temperature in thin-films of the helimagnet FeGe with magnetic chirality inversion of the SkX across lattice twin boundaries will pave a new path to designing quantum-effect devices based on the controllable skyrmion dynamics.
Journal ArticleDOI
Observation of room-temperature magnetic skyrmions and their current-driven dynamics in ultrathin metallic ferromagnets
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TL;DR: In this paper, stable magnetic skyrmions at room temperature in ultrathin transition metal ferromagnets with magnetic transmission soft X-ray microscopy were observed and demonstrated.
Journal ArticleDOI
Multiferroicity: the coupling between magnetic and polarization orders
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Weak ferromagnetism and magnetoelectric coupling in bismuth ferrite
Claude Ederer,Nicola A. Spaldin +1 more
TL;DR: In this paper, the coupling between the ferroelectric and magnetic order parameters in the magnetoelectric multiferroic was analyzed using density functional theory within the local spin density approximation (LSDA) and the $\mathrm{LSDA}+\mathm{U}$ method.
Journal ArticleDOI
Copper Active Sites in Biology
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