Berlin 2008 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 21: Magnetic Thin Films II
MA 21.7: Vortrag
Mittwoch, 27. Februar 2008, 15:30–15:45, H 1012
Magnetic and Transport Properties of doped EuO Thin Films — •S. Altendorf1, R. Sutarto1, M. Moretti2, T. Haupricht1, and L. H. Tjeng1 — 1II. Physikalisches Institut, Universität zu Köln, Germany — 2Dipartimento di Fisica, Politecnico di Milano, Italy
Europiumoxide (EuO) is a ferromagnetic semiconductor with a bandgap of
1.12 eV at room temperature and a Curie temperature of 69 K. In slightly
Eu-rich EuO, the magnetic transition is accompanied by a metal-insulator
transition with an unprecedented large change in resistivity up to 13
orders of magnitude. Spin-polarized electron spectroscopies revealed
that the charge cariers are moving in an essentially fully spin-polarized
band [1]. Eu-rich EuO also exhibits an increase of TC up to 150 K [2].
Similarly, in Gd-doped EuO thin films, TC can be enhanced up to 170 K
with Gd concentration of about 4 % [3]. However, as to whether a MIT
occurs in Gd-doped EuO is still an open question [2,4].
We report our results of in situ measurements of the magnetic and
transport properties of EuO thin films prepared by means of molecular beam
epitaxy technique in a distillation method [1,3] which allows a precise
control and tuning of the stoichiometry. The connection between the
magnetic order and metal-insulator transition of Eu-rich and Gd-doped EuO
thin films was investigated.
[1] P. G. Steeneken et al., Phys. Rev Lett.
88 047201 (2002) [2] T. Matsumoto, et al., J. Phys.:
Condens. Matter 16, 6017 (2004) [3] H. Ott, et al.,
Phys. Rev. B 73, 094407 (2006) [4] J. Schoenes et al.,
Phys. Rev B 9. 3097 (1974)