Dresden 2006 – scientific programme

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MA: Magnetismus

MA 24: Magnetic Thin Films III

MA 24.6: Talk

Thursday, March 30, 2006, 11:30–11:45, HSZ 03

Fe-doped MgO thin films in the impurity limit — •R. Sutarto¹, T. Haupricht¹, H. Ott¹, M. W. Haverkort¹, A. Tanaka², H. -H. Hsieh³, H. -J. Lin⁴, C. T. Chen⁴, and L. H. Tjeng¹ — ¹II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany — ²Department of Quantum Matter, ADSM, Hiroshima University, Higashi-Hiroshima 739-8530, Japan — ³Chung Cheng Institute of Technology, National Defense University, Taoyuan 335, Taiwan — ⁴National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu 30077, Taiwan

Epitaxial Fe-doped MgO thin films at different doping levels from 1% to 30% have been successfully grown using Molecular Beam Epitaxy (MBE). Fe L_2,3 x-ray absorption spectra (XAS) of Fe-doped MgO at 1-2% Fe doping levels shows a striking narrow peak indicating that non-local effects of inter-Fe-site fluctuations are strongly suppressed. The experimental results in this impurity limit are well reproduced using FeO₆ cluster calculations with O_h symmetry, implying that the film is an excellent reference sample for a d⁶ high spin state system. Moreover, this cluster model simulates well the observed temperature dependence of the XAS spectra caused by thermal population of the spin-orbit split initial states.