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تسجيل مستخدم جديدComplex nature of exchange splitting in oxide ferromagnets: A spin-resolved photoemission study of EuO
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The electronic structure of the ferromagnetic semiconductor EuO is investigated by means of spin- and angle-resolved photoemission spectroscopy and density functional theory. Our spin-resolved data reveals that, while the macroscopic magnetization of the sample vanishes at the Curie temperature $T_C$, the experimentally-determined exchange splitting of the O 2$p$ band persists at least up to $T_{C}$ if the picture of fluctuating spin-blocks is assumed. We discuss possible temperature-related spectral changes by analyzing ferromagnetic and antiferromagnetic phases, directional effect due to spin orbit coupling, as well as effects due to sample aging. Our calculations with a Hubbard $U$ term reveal a complex nature of the local exchange splitting on the oxygen site and in conduction bands, shining a new light on the interpretation of previous optical and photoemission spectroscopic results.
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High quality thin films of the ferromagnetic semiconductor EuO have been prepared and were studied using a new form of spin-resolved spectroscopy. We observed large changes in the electronic structure across the Curie and metal-insulator transition t
emperature. We found that these are caused by the exchange splitting of the conduction band in the ferromagnetic state, which is as large as 0.6 eV. We also present strong evidence that the bottom of the conduction band consists mainly of majority spins. This implies that doped charge carriers in EuO are practically fully spin polarized.
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