Resonant photoemission spectroscopy study of insulator-to-metal   transition in Cr- and Ru-doped Nd_{1/2}A_{1/2}Mn_{1-y} O_{3} (A=Ca, Sr)
  Electronic structures of very dilute Cr- or Ru-doped Nd_{1/2}A_{1/2}MnO_{3} (NAMO; A=Ca, Sr) manganites have been investigated using the Mn and Cr 2p -> 3d resonant photoemission spectroscopy (PES). All the Cr- and Ru-doped NAMO systems exhibit the clear metallic Fermi edges in the Mn e_g spectra near E_F, consistent with their metallic ground states. The Cr 3d states with t^3_{2g} configuration are at ~ 1.3 eV below E_F, and the Cr e_{g} states do not participate in the formation of the band near E_F. Cr- and Ru-induced ferromagnetism and insulator-to-metal transitions can be understood with their measured electronic structures. 
J. -S. Kang, J. H. Kim, A. Sekiyama, S. Kasai, S. Suga, S. W. Han, K.   H. Kim, E. J. Choi, T. Kimura, T. Muro, Y. Saitoh, C...