X-ray Absorption and Photoemission Spectroscopy Study of Nd_1/2A_1/2Mn_1-yCr_yO₃(A=Ca, Sr)

Valence states and electronic structures of Cr-doped $Nd_1/2A_1/2Mn_1-yCr_yO_3$(NAMO; A=Ca, Sr) manganites have been investigated using x-ray absorption spectroscopy (XAS) and high-resolution photoemission spectroscopy (PES). All the Cr-doped NAMO systems exhibit the clear metallic Fermi edges in the Mn $e_g$ PES spectra near $E_F$. The spectral intensity at $E_F$ is higher for Cr-doped N $d_l$ 2/S $r_l$ 2/Mn $O_3$(NSMO) than for Cr-doped N $d_l$ 2/C $a_l$ 2/Mn $O_3$ (NCMO), reflecting the stronger metallic nature for NSMO than for NCMO. The measured Cr 2p XAS spectra are found to be very similar to that of C $r_2$ $O_3$, indicating that Cr ions in Cr-doped NAMO are in the trivalent C states ( $t^3$$_2g$). The Cr 2p XAS data are consistent with the Cr 3d PES spectra located at ∼1.3 eV below $E_F$ and having no emission near $E_F$.