TEMPERATURE-DEPENDENCE OF THE ELECTRONIC-STRUCTURE OF THE CHARGE-ORDERING MANGANITE PR0.5SR0.5MNO3

We study the changes in the occupied density of states of Pr0.5Sr0.5Mn O3 as a function of temperature (25-300 K) using photoemission spectro scopy. The spectral weight transfer across the or/charge-ordering/ferr omagnetic-antiferromagnetic transition is abrupt and over very large e nergy scales (up to 1.2 eV from the Fermi level E-F) compared to the t ransition temperature T-mi=140 K (similar to 12 meV) and the gap value in the insulating phase (similar to 100 meV). Negligible changes obse rved at E-F in the ferromagnetic-metallic phase above T-mi and a weak spectral weight transfer across the ferromagnetic-paramagnetic transit ion at T-fp=270 K are consistent with negligible change in carrier den sity above T-mi.