Berlin 2008 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 20: Multiferroics

MA 20.4: Vortrag

Mittwoch, 27. Februar 2008, 14:45–15:00, EB 202

(Sr,Mn)TiO₃ - a magnetoelectric multiglass — •Subhankar Bedanta¹, Vladimir Shvartsman¹, Pavel Borisov¹, Wolfgang Kleemann¹, Alexander Tkach², and Paula Vilarinho² — ¹Angewandte Physik, Universität Duisburg-Essen, D-47048 Duisburg, Germany — ²Department of Ceramics and Glass Engineering, CICECO, University of Aveiro, 3810-193 Aveiro, Portugal

In recent years there has been a growing interest in studies of multiferroic materials, in which two or more ferroically ordered states - usually long-range polar and magnetic order - exist simultaneously. In this work we extend this frame onto the simultaneous occurrence of two different glassy states, hence, looking for a "multiglass" scenario rather than for a multiferroic one. This is realized in Sr_0.98Mn_0.02TiO₃ ceramics [1] where the Mn²⁺ dopand ions are at the origin of both a polar cluster and a magnetic spin glass. Both the temperature dependencies of the magnetization, M(T), and of the magnetic susceptibility, χ(T), show an anomaly around 38 K [2]. On the other hand, this temperature corresponds to the polar glass transition, indicating a correlation between magnetic and polar order. Both glassy states are unambiguously and independently evidenced by their specific aging and memory effects. In addition, higher order magnetoelectric coupling between the polar and magnetic degrees of freedom is observed [2].
A. Tkach et al., Appl. Phys. Lett. 86, 172902 (2005).
S. Bedanta et al., in press