Resonant X-Ray Scattering from Orbital Ordering inLaMnO3

著者: Youichi Murakami, J. P. Hill, D. Gibbs, M. Blume, Ichiro Koyama, M. Tanaka, Hiroshi Kawata, T. Arima, Y. Tokura, K. Hirota, Y. Endoh - Physical Review Letters 1998 被引用: 600

Dipole resonant x-ray scattering from ordered Mn $3d$ orbitals in $\mathrm{LaMn}{\mathrm{O}}_{3}$ has been observed near the Mn $K$-absorption edge. The polarization of the scattered photons is rotated from $\ensuremath{\sigma}$ to ${\ensuremath{\pi}}^{\ensuremath{'}}$ and the azimuthal angle dependence shows a characteristic twofold symmetry. A theory for the resonant scattering mechanism has been developed by considering the splitting of the Mn $4p$ levels due to the Mn $3d$ orbital ordering. The order parameter of the orbital ordering decreases above the N\'eel temperature ( ${T}_{N}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}140\mathrm{K}$) and disappears at ${T}_{O}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}780\mathrm{K}$, concomitant with a structural phase transition.