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MA: Fachverband Magnetismus

MA 16: Multiferroics I (jointly with DF, DS, KR, TT)

MA 16.3: Vortrag

Dienstag, 1. April 2014, 10:00–10:15, BEY 118

Lattice and polarizability mediated spin activity in EuTiO3 — •Annette Bussmann-Holder¹, Kevin Caslin^{1, 2}, Patrick Reuvenkamp¹, Zurab Guguchia³, Hugo Keller³, Reinhard Kremer¹, and Jürgen Köhler¹ — ¹Max Planck Institute for Solid State Research, Heisenbergstr.1, D-70569 Stuttgart, Germany — ²Brock University, 500 Glenridge Ave., St. Catharines L2S-3A1, Ontario, Canada — ³Physik-Institut der Universität Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland

EuTiO3 is shown to exhibit novel strong spin-charge-lattice coupling deep in the paramagnetic phase. Its existence is evidenced by an, until now, unknown response of the paramagnetic susceptibility at temperatures exceeding the structural phase transition temperature TS=282K. The extra features in the susceptibility follow the rotational soft zone boundary mode temperature dependence above and below TS. In addition, novel magnetostriction experiments and dielectric constant measurements have been performed which both reveal giant anomalies related to the antiferromagnetic phase transition at TN=5.7K and the structural phase transition at TS. The theoretical modeling consistently reproduces these anomalies and provides evidence that EuTiO3 has considerable analogies to SrTiO3 but also substantial differences stemming from the Eu 4f spins which are lattice activated at high temperatures far above TN.