Electronic structures of the CMR perovskites R(1-x)A(x)MnO(3) (R = La, Pr; A = Ca, Sr, Ce) using photoelectron spectroscopy

Abstract

Using photoelectron spectroscopy, the electronic structures of the CMR (colossal magneto-resistance) manganites of Pr1-xSrxMnO3 (PSMO; x = 1/3, 1/2, 2/3), La0.7Ca0.3Mn0.95T0.05O3 (LCMTO; T = Fe, Co. Ni). and La0.7Ce0.3MnO3 (LCeMO) have been-investigated. Mn 2p spectra of PSMO and LCMTO are found to be very similar for different x values and different T elements, probably due to the large multiplet splitting of the Mn 2p core levels for both Mn3+ and Mn4+ ions, The line-shape analysis shows that the Mn 2p spectra can be interpreted as consisting of exchange-split components. The La and Pr 3d(5/2) spectra of LCMTO and PSMO indicate large La/Pr 4f-O 2p hybridization in these manganites. The Ce 3d spectrum of LCeMO reveals nearly tetravalent Co ions. suggesting that the double-exchange mechanism may be operative in LCeMO. The Sr 3d spectra of PSMO exhibit two components, with the high binding-energy component increasing with increasing x. Valence-band spectra of PSMO and LCMTO are very similar to one another. suggesting that the Mn 3d-O 2p hybridization is dominant in PSMO and LCMTO.