Regensburg 2013 – scientific programme
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DF: Fachverband Dielektrische Festkörper
DF 16: Dielectric and ferroelectric thin films
DF 16.1: Talk
Wednesday, March 13, 2013, 10:40–11:00, H11
Magnetic field enhanced structural instability in EuTiO3 — •Annette Bussmann-Holder1, Jürgen Köhler1, Zurab Guguchia2, and Hugo Keller2 — 1Max-Planck-Institute for Solid State Research, Stuttgart, Germany — 2Physik Institut der Universität Zürich, Zürich, Switzerland
EuTiO3 undergoes a structural phase transition from cubic to tetragonal at TS=282K which is not accompanied by any long range magnetic order. However, it is related to the oxygen ocathedra rotation driven by a zone boundary acoustic mode softening. Here we show that this displacive second order structural phase transition can be shifted to higher temperatures by the application of an external magnetic field (ΔTS~4K for *0H=9T). This observed field dependence is in agreement with theoretical predictions based on a coupled spin-anharmonic-phonon interaction model. The observed magnetic field dependence of TS demonstrates that a strong spin-phonon coupling is present in this compound already at high temperatures which suggests that spin fluctuations are present at these temperatures most likely driven by the oxygen ion octahedral rotation.