Electronic States of Collosal Magnetoresistive Manganites La0.67Pb0.33Mn1-xFexO3 from Photoemission Spectroscopy

M. Kowalika, b, R. Zaleckia and A. Kołodziejczyka a Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Kraków, Poland b Department of Physics, Rzeszów University of Technology, Powstańców Warszawy 6, 35-959 Rzeszów, Poland

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The electron photoemission spectra of valence bands and core-level states of manganese perovskite La0.67Pb0.33(Mn1-xFex)O3 with x = 0, 0.01, 0.03, 0.06, 0.10 and 0.15 were measured by the X-ray and Ultraviolet Photoemission Spectroscopy (XPS and UPS) below and above the metal-insulator transition. From analysis of the Mn 2p core-level spectra the ratio Mn3+/Mn4+ was calculated as a function of the iron content. Comparison of the valence band spectrum with band structure calculations and with the high-resolution spectra measured at synchrotron radiation for Ca-, Ba- and Ce- substituted manganites revealed the strong hybridisation of Mn 3d and of O 2p states between -3 eV and -7 eV, and no estimated oxygen states between 0 eV and -2 eV where the Mn-3d states play a predominant role. The composition dependent insulating energy gaps were measured at room temperature. Reasons for the behaviour were discussed taking into account previous analysis of XPS/UPS spectra of other manganese perovskites.

DOI: 10.12693/APhysPolA.117.277 PACS numbers: 71.20.Lp, 79.60.Bm, 71.15.Ap, 74.20.Mn