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.
Download