Regensburg 2007 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 11: Poster Session

DF 11.26: Poster

Donnerstag, 29. März 2007, 14:30–18:00, Poster C

Magnetic properties of Mn-doped Strontium Titanate — Subhankar Bedanta¹, •Vladimir V. Shvartsman¹, Wolfgang Kleemann¹, Alexander Tkach², and Paula M. Vilarinho² — ¹Angewandte Physik, Universität Duisburg-Essen, D-47048 Duisburg, Germany — ²Department of Ceramics and Glass Engineering, CICECO, University of Aveiro, 3810-193 Aveiro, Portugal

Over the last decades there has been a growing interest in studies of incipient ferroelectrics doped with different impurities. In particular, relaxor-type behaviour was found recently in Sr_1−xMn_xTiO₃ (SMnT) ceramics with a moderate Mn content (x≤0.03) [1, 2]. Furthermore, the Mn-doping may induce distinct magnetic properties. We studied them on SMnT with x = 0.02 by SQUID magnetometry and ac-susceptometry. Both the temperature dependencies of the magnetization, M(T), and of the magnetic susceptibility, χ(T), show an anomaly around 35 K. Below this temperature magnetic hysteresis is found. On the other hand, the dielectric permittivity shows a maximum in the same temperature range [2] indicating a correlation between polar and magnetic order. Efforts are put into understanding, if the observed magnetic behaviour at low temperatures might be due to superparamagnetic cluster formation or to a magnetically ordered state. A possible coupling between dielectric and magnetic properties is discussed.
A. Tkach et al., Appl. Phys. Lett. 86, 172902 (2005).
A. Tkach et al., Phys. Rev. B 73, 104113 (2006).