Magnetization-dependent behaviors of interband transitions between the exchange-split bands in doped manganite films

The temperature dependence of absorption spectra for thin films of double-exchange ferromagnet R0.6Sr0.4MnO3 has been investigated with variation of the one-electron bandwidth W. With decreasing temperature, which corresponds to the increase of the magnetization M, a large amount of spectral weight transfers from the high-(similar to 3 eV) to low-(less than or equal to 1 eV) energy region. We ascribe these transitions to the interband transition between the bands split by the on-site exchange interaction J and the intraband transition within the lower band, respectively. This suggests that optical excitations in the visible region strongly couple with local spin alignments in these doped manganites.