Resonant photoemission spectroscopy study of impurity-induced melting in Cr- and Ru-doped Nd(1/2)A(1/2)MnO(3) (A=Ca,Sr)

Abstract

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(2g)(3) configuration are at similar to1.3 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 based on their measured electronic structures.