Berlin 2012 – wissenschaftliches Programm
MA 19: Joint Session "Multiferroics III - Strain / New Routes towards Multiferroicity" (jointly with DF, DS, KR, TT)
MA 19.2: Vortrag
Dienstag, 27. März 2012, 09:45–10:00, EB 301
Directly probing the effect of strain on magnetic exchange interactions — •Kathrin Dörr1,2, Andreas Herklotz2, Hans-Martin Christen3, and Michael Biegalski3 — 1MLU Halle Wittenberg, Von-Danckelmann-Platz 3, 06120 Halle — 2IFW Dresden, Postfach 270116, 01171 Dresden — 3CNMS, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
Thin films of transition metal oxides of the perovskite type ABO3 (B = 3d or 4d metal) have revealed abundant examples for strain-driven changes of magnetic ordering. In spite of strong efforts, the theoretical treatment of magnetic exchange in complex oxides has remained a challenge, and experiments continue to show unpredicted large effects of the epitaxial strains in films. In order to provide meaningful experimental data on strain dependences, epitaxial thin films should be grown in various coherent strain states on different substrates without changing anything but the strain. This is inherently difficult: possible problems arise from a strain-dependent oxidation level or microstructure. As a complementary approach, the in-plane strain of epitaxial oxide films can be controlled reversibly by 0.1-0.2 percent using a piezoelectric substrate. I will address reversible-strain studies on La0.7Sr0.3MnO3, La1−xSrxCoO3 (x = 0, 0.2, 0.3) und SrRuO3 films, showing the strain response of the magnetic Curie temperature and the magnetization and discussing the current understanding of the strain effects on magnetic ordering.