Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 14: Electronic Structure of Surfaces: Magnetism and Spin Phenomena II
O 14.1: Vortrag
Montag, 20. März 2017, 15:00–15:15, WIL C107
Exchange Splitting above the Curie Temperature in EuO — •Timm Gerber1, Markus Eschbach1, Tristan Heider1, Ewa Mlynczak1, Patrick Lömker1, Pika Gospodaric1, Mathias Gehlmann1, Moritz Plötzing1, Okan Köksal2, Rossitza Pentcheva2, Lukasz Plucinski1,2, Claus M. Schneider1,2, and Martina Müller1,2 — 1Peter Grünberg Institut (PGI-6), Forschungszentrum Jülich GmbH, Germany — 2Fakultät für Physik and CENIDE, Universität Duisburg-Essen, Germany
The ferromagnetic semiconductor europium monoxide (EuO) is an efficient spin filter and, therefore, an attractive material for fundamental research in the field of spintronics [1,2]. Although EuO is considered to be a Heisenberg ferromagnet, a Stoner-like vanishing of the conduction band’s exchange splitting is typically observed [3].
We investigated the electronic structure of EuO by means of spin- and angle-resolved photoemission spectroscopy (spinARPES) complemented by DFT + U calculations. Our spin-resolved data reveals a complex temperature dependence of the occupied density of states which can not be accessed by spin-integrated ARPES measurements [4]. We show that the exchange splitting of the O 2p band persists up to the Curie temperature and even above. Our findings indictate that sizeable short range magnetic order in EuO is present above TC.
[1] M. Müller et. al., J. Appl. Phys. 105, 07C917 (2009)
[2] A. Schmehl et. al., Nat. Mater. 6, 882 (2007)
[3] M. Freiser et al., Helv. Phys. Acta 41, 832 (1968).
[4] H. Miyazaki et. al., Phys. Rev. Lett. 102, 227203 (2009)