Dwivedi, G. D. and Joshi, Amish G. and Kumar, Shiv and Chou, H. and Yang, K. S. and Jhong, D. J. and Chan, W. L. and Ghosh, A. K. and Chatterjee, Sandip
(2016)
Electronic structure study of wide band gap magnetic semiconductor (La0.6Pr0.4)(0.65)Ca0.35MnO3 nanocrystals in paramagnetic and ferromagnetic phases.
Applied Physics Letters , 108 (17).
172402-1-172402-5.
ISSN 0003-6951
Abstract
X-ray circular magnetic dichroism (XMCD), X-ray photoemission spectroscopy (XPS), and ultraviolet photoemission spectroscopy (UPS) techniques were used to study the electronic structure of nanocrystalline (La0.6Pr0.4)(0.65)Ca0.35MnO3 near Fermi-level. XMCD results indicate that Mn3+ and Mn4+ spins are aligned parallel to each other at 20 K. The low M-H hysteresis curve measured at 5K confirms ferromagnetic ordering in the (La0.6Pr0.4)(0.65)Ca0.35MnO3 system. The low temperature valence band XPS indicates that coupling between Mn3d and O2p is enhanced and the electronic states near Fermi-level have been suppressed below T-C. The valence band UPS also confirms the suppression of electronic states near Fermi-level below Curie temperature. UPS near Fermi-edge shows that the electronic states are almost absent below 0.5 eV (at 300K) and 1 eV (at 115K). This absence clearly demonstrates the existence of a wide band-gap in the system since, for hole-doped semiconductors, the Fermi-level resides just above the valence band maximum.
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