Gigantic Kerr rotation induced by a d-d transition resonance in M Cr 2 S 4 (M=Mn,Fe)
Gigantic Kerr rotation induced by a d-d transition resonance in M Cr 2 S 4 (M=Mn,Fe)
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DOI：
10.1103/physrevb.72.155114
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发表时间：
2005-10
影响因子：
3.7
通讯作者：
K. Ohgushi;T. Ogasawara;Y. Okimoto;S. Miyasaka;Y. Tokura;Y. Tokura
中科院分区：
文献类型：
--
作者：
K. Ohgushi;T. Ogasawara;Y. Okimoto;S. Miyasaka;Y. Tokura;Y. Tokura
The magneto-optical Kerr effect (MOKE) has been investigated for ferrimagnetic spinel compounds $M{\mathrm{Cr}}_{2}{\mathrm{S}}_{4}$ ($M=\mathrm{Mn}$ and Fe). In $\mathrm{Fe}{\mathrm{Cr}}_{2}{\mathrm{S}}_{4}$, the gigantic magneto-optical response, reaching up to 4.3\ifmmode^\circ\else\textdegree\fi{} in Kerr rotation, is observed at the energy of the intra-atomic $d\text{\ensuremath{-}}d$ transition of ${\mathrm{Fe}}^{2+}$, $^{5}E\ensuremath{\rightarrow}^{5}T_{2}$. By analyzing the resonance feature in the framework of the ligand field theory, we have clarified that the large oscillator strength enhanced by the strong covalency of the ligand sulfur as well as the local breakdown of inversion symmetry at the ${\mathrm{Fe}}^{2+}$ site is responsible for the gigantic signal. In $\mathrm{Mn}{\mathrm{Cr}}_{2}{\mathrm{S}}_{4}$, the spin-forbidden $d\text{\ensuremath{-}}d$ transition $(^{6}A_{1}\ensuremath{\rightarrow}^{4}T_{1})$ of ${\mathrm{Mn}}^{2+}$ is revealed in the MOKE spectra, which is not discernible in the optical reflectivity spectra.
The magneto-optical Kerr effect (MOKE) has been investigated for ferrimagnetic spinel compounds $M{\mathrm{Cr}}_{2}{\mathrm{S}}_{4}$ ($M=\mathrm{Mn}$ and Fe). In $\mathrm{Fe}{\mathrm{Cr}}_{2}{\mathrm{S}}_{4}$, the gigantic magneto-optical response, reaching up to 4.3\ifmmode^\circ\else\textdegree\fi{} in Kerr rotation, is observed at the energy of the intra-atomic $d\text{\ensuremath{-}}d$ transition of ${\mathrm{Fe}}^{2+}$, $^{5}E\ensuremath{\rightarrow}^{5}T_{2}$. By analyzing the resonance feature in the framework of the ligand field theory, we have clarified that the large oscillator strength enhanced by the strong covalency of the ligand sulfur as well as the local breakdown of inversion symmetry at the ${\mathrm{Fe}}^{2+}$ site is responsible for the gigantic signal. In $\mathrm{Mn}{\mathrm{Cr}}_{2}{\mathrm{S}}_{4}$, the spin-forbidden $d\text{\ensuremath{-}}d$ transition $(^{6}A_{1}\ensuremath{\rightarrow}^{4}T_{1})$ of ${\mathrm{Mn}}^{2+}$ is revealed in the MOKE spectra, which is not discernible in the optical reflectivity spectra.