Berlin 2012 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 46: MagneticThin Films II
MA 46.5: Vortrag
Donnerstag, 29. März 2012, 16:00–16:15, EB 202
Spectroscopic observation of strain-assisted TC enhancement in EuO upon Gd doping — •S. G. Altendorf1,2, N. Hollmann2, R. Sutarto1,3, C. Caspers1, R. C. Wicks3, Y.-Y. Chin1,2, Z. Hu1,2, H. Kierspel1, I. S. Elfimov3, H. H. Hsieh4, H.-J. Lin5, C. T. Chen5, and L. H. Tjeng1,2 — 1II. Physikalisches Institut, Universität zu Köln — 2Max Planck Institute for Chemical Physics of Solids, Dresden — 3Department of Physics and Astronomy, University of British Columbia, Canada — 4Chung Cheng Institute of Technology, Taoyuan, Taiwan — 5National Synchrotron Radiation Research Center, Hsinchu, Taiwan
EuO is a ferromagnetic semiconductor which, upon electron doping, shows a wealth of spectacular phenomena including insulator-to-metal transition and colossal magnetoresistance. Moreover, the doped charge carriers are propagating in an almost 100% spin polarized band, making EuO to be an attractive candidate for spintronics. To facilitate the use of EuO in device applications, it is important to increase the relatively low Curie temperature. The origin of the TC enhancement of EuO upon Gd doping is studied using soft x-ray absorption spectroscopy on pure and Gd-doped EuO thin films. Temperature and doping dependent changes in the oxygen K edge spectra provide information about the correlation of magnetism and lattice. Band structure calculations reveal that these spectral changes and the increase of TC to 125 K for Gd-doped EuO cannot be explained by electron doping alone. The compression of the crystal lattice due to the incorporation of the smaller Gd3+ ions plays also an important role.