Optical Investigations of YbCrO₃. III. Cr³⁺ Exciton—Yb³⁺ Spin Flip Simultaneous Absorption

抄録

Absorption spectra corresponding to the ⁴A_2g→²E_g transition of Cr³⁺ in YbCrO₃ were studied. In the lowest energy region, R exciton lines with Davydov splitting were observed, and the magnitudes of the inter-sublattice exciton transfers were obtained by the analysis of these spectra. In the shorter wave length side of R exciton lines, a band(R′) of electric dipole character was observed, which has an anomalous shape with a sharp cut-off at the lowest energy side and fine structure. The temperature and magnetic field dependences of R′ band suggest that it corresponds to the simultaneous excitation of a Cr³⁺ exciton and a spin flip of the Yb³⁺ ground state. From the analysis of the anomalous shape of R′ band, a negative dispersion of the Cr³⁺ exciton was found to be −16 cm⁻¹.