Directionally dependent magneto-optical response of (La0.4Pr0.6)1.2Sr1.8Mn2O7:: Understanding the high-field ferromagnetic metallic state -: art. no. 064425

We investigate the polarized magneto-optical response of (La0.4Pr0.6)(1.2)Sr1.8Mn2O7 in order to reveal the microscopic nature of the states involved in the field-induced paramagnetic semiconductor to ferromagnetic metal transition. We find significant changes in the electronic structure of the title compound under magnetic fields due to the evolution of the Jahn-Teller-split Mn3+ e(g) orbitals. Consequences of this field-induced modification of the d orbitals include the substantial colossal magnetoresistence effect, unusual magnetic relaxation behavior, and a change in orbital occupation. Based upon the directional dependence of the magneto-optical spectra, we demonstrate that the high-field ferromagnetic state is homogeneous.