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 Ln1-xAxMnO3 (Ln = La, Pr ; A = Ca, Sr, Ba; 0 ≤ x ≤ 0.33) exhibiting GMR properties have been investigated above and below the transition temperature by soft X-ray Absorption Spectroscopy at Mn L2,3-edge. The analysis of the Mn L3-edges both in the paramagnetic-insulating state and in the metallic-ferromagnetic state have been performed by a linear combination of a Mn(IV) reference and two simulated spectra corresponding to High Spin and Low Spin Mn(III). The results of the simulation, although not perfect, indicate that, upon crossing the transition, a change occurs in the ratio HS/LS of Mn(III) states