ELECTRONIC-STRUCTURE OF MANGANESE IN GMR PEROVSKITES AS SEEN BY THE SOFT-X-RAY ABSORPTION-SPECTROSCOPY

The changes in the electronic structure of manganese perovskites Ln(1- X)A(X)MnO(3) (Ln = La, Pr; A = Ca, Sr, Ba; 0 less than or equal to x l ess than or equal to 0.33) exhibiting GMR properties have been investi gated above and below the transition temperature by soft X-ray Absorpt ion Spectroscopy at Mn L-2,L-3-edge. The analysis of the Mn L-3-edges both in the paramagnetic-insulating state and in the metallic-ferromag netic stale have been performed by a linear combination of a Mn(IV) re ference and two simulated spectra corresponding to High Spin and Low S pin Mn(III). The results of the simulation, although not perfect, indi cate that, upon crossing the transition, a change occurs in the ratio HS/LS of Mn(III) states.