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
Interface magnetism in Fe 2 O 3 /FeTiO 3 heterostructures
TL;DR: In this paper, a phase diagram of the stability with respect to the end members of the Fe(2)O(3)/FeTiO(4+) system is presented, showing that magnetism is associated with impurity levels in the band gap.
Journal ArticleDOI
Magnetic structure of monatomic Fe chains on Re(0001): Emergence of chiral multispin interactions
András Lászlóffy,Levente Rózsa,Krisztián Palotás,Krisztián Palotás,Krisztián Palotás,László Udvardi,László Szunyogh +6 more
TL;DR: In this paper, first-principles calculations of the magnetic properties of Fe chains deposited on the Re(0001) surface were presented, and it was shown that a classical spin model derived from the ab initio calculations containing only two-spin interactions supported opposite chirality of the spin spiral compared to a direct optimization of spin configuration within the ab- initio method.
Journal ArticleDOI
Electromagnon dispersion probed by inelastic X-ray scattering in LiCrO 2
Sándor Tóth,Björn Wehinger,Björn Wehinger,Katharina Rolfs,Turan Birol,Uwe Stuhr,Hiroshi Takatsu,Kenta Kimura,Tsuyoshi Kimura,Henrik M. Rønnow,Christian Rüegg,Christian Rüegg +11 more
TL;DR: The observation of strong magnon–phonon coupling in LiCrO2 that enables the measurement of magnetic correlations throughout the Brillouin zone via IXS and predicts that several (frustrated) magnets with dominant direct exchange and non-collinear magnetism show surprisingly large IXS cross-section for magnons and multi-magnon processes.
Journal ArticleDOI
Dynamical magnetoelectric phenomena of multiferroic skyrmions
TL;DR: It is argued that multiferroic skyrmions show unique coupled oscillation modes of magnetizations and polarizations, so-called electromagnon excitations, which are both magnetically and electrically active, and interference between the electric and magnetic activation processes leads to peculiar magnetoelectric effects in a microwave frequency regime.
Journal ArticleDOI
Detrimental Effect of Interfacial Dzyaloshinskii-Moriya Interaction on Perpendicular Spin-Transfer-Torque Magnetic Random Access Memory
TL;DR: Recently, perpendicular magnetic anisotropy based spin-transfer torque magnetic random access memory (STT-MRAM) is drawing a great attention to researchers studying MRAM due to its advantages of having the density of DRAM, fast response time of SRAM and the nonvolatility of flash memory as mentioned in this paper.