Berlin 2012 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 52: Poster II - Magnetic Heusler compounds, Magnetic shape memory alloys, Thin Films, Micro-/Nano-structured magnetic materials, Graphene, Spins in organics, Magnetic imaging, Surface Magnetism, Spin excitations/Torque, Spincaloric transport

MA 52.20: Poster

Freitag, 30. März 2012, 11:00–14:00, Poster A

Magnetic anisotropy of strained La_0.7Sr_0.3CoO₃ thin films probed by XMCD — •Felix Eilers^1,2, Michael Merz¹, Dirk Fuchs¹, Hilbert von Löhneysen^1,3, Peter Nagel¹, and Stefan Schuppler¹ — ¹KIT, Institut für Festkörperphysik — ²KIT, Fakultät für Physik — ³KIT, Physikalisches Institut, Karlsruhe, Germany

The magnetic properties of perovskite-type La_1−xSr_xCoO₃ have their origin in the variety of possible valence and spin states of the Co ion and in strong electronic correlations. Bulk La_0.7Sr_0.3CoO₃ is known to be a ferromagnetic metal below T_C ≈ 240 K and to exhibit large Joule magnetostriction. This motivated us to investigate a complementary magnetoelastic effect: the effect of biaxial strain on the magnetization.

La_0.7Sr_0.3CoO₃ thin films were grown on lattice-mismatched substrates (LaAlO₃ and LSAT) by pulsed laser deposition. X-ray diffraction confirmed the films to be subjected to compressive or tensile strain, respectively. Near-edge x-ray absorption fine structure (NEXAFS) and x-ray magnetic circular dichroism (XMCD) at the Co L_2,3 edge and the O K edge provided spectroscopic information on the electronic and magnetic structure. Sum rules were used to extract magnetic moments from the XMCD spectra. The difference between in-plane and out-of-plane magnetic moments was found to vary with the biaxial strain.

We gratefully acknowledge the Max Planck Institute for Intelligent Systems (E. Goering, T. Tietze, G. Schütz) for the use of their XMCD end station and the synchrotron light source ANKA for the provision of beam time.