Bulk-sensitive photoemission spectroscopy of A_2FeMoO_6 double   perovskites (A=Sr, Ba)
  Electronic structures of Sr_2FeMoO_6 (SFMO) and Ba_2FeMoO_6 (BFMO) double perovskites have been investigated using the Fe 2p->3d resonant photoemission spectroscopy (PES) and the Cooper minimum in the Mo 4d photoionization cross section. The states close to the Fermi level are found to have strongly mixed Mo-Fe t_{2g} character, suggesting that the Fe valence is far from pure 3+. The Fe 2p_{3/2} XAS spectra indicate the mixed-valent Fe^{3+}-Fe^{2+} configurations, and the larger Fe^{2+} component for BFMO than for SFMO, suggesting a kind of double exchange interaction. The valence-band PES spectra reveal good agreement with the LSDA+U calculation. 
J. -S. Kang, J. H. Kim, A. Sekiyama, S. Kasai, S. Suga, S. W. Han, K.   H. Kim, T. Muro, Y. Saitoh, C. Hwang, C. G. Olson, B...