Dresden 2006 – wissenschaftliches Programm

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MA: Magnetismus

MA 20: Poster: Films(1-36) Transp(37-56) Ex.Bias(57-67) Spindyn(68-80) Micromag(81-95) Particle(96-109) Imag.+Surface(110-113) Spinelectr(114-122) Theory+Micromag(123-131) Spinstr+Aniso(132-142) MagMat(143-156) Meas(157,158) MolMag+Kondo(159-162) Postdead(163-)

MA 20.133: Poster

Dienstag, 28. März 2006, 15:15–19:15, P1

Thermal transport in multiferroics — •K. Berggold¹, T. Lorenz¹, J. Baier¹, D. Meier¹, J. Hemberger¹, D. Argyriou², A. Vasiliev³, and J. Hemberger^1,4 — ¹II. Physikalisches Institut, University of Cologne, Germany — ²Hahn-Meitner-Institut, 14109 Berlin, Germany — ³Moscow State University, Moscow 119992, Russia — ⁴Inst. f. Physik, University of Augsburg, Germany

There is a growing interest in multiferroic systems, since they show large magnetocapacitive effects, and for this offer interesting prospects with respect to application. One tool to investigate the interplay between electric and magnetic excitations is to study the thermal conductivity κ in magnetic fields. Recently, large multiferroic effects have been found in RMnO₃ compounds[1]. TbMnO₃ has the most complex phase diagram of these series, and allows to flip the electric polarization by a magnetic field. We present measurements of κ along the a direction with magnetic fields applied in the different crystallographic directions. A huge magnetic-field dependence of κ(B) is observed at the phase boundaries. Recently, GdFe₃(BO₃)₄ was introduced as another multiferroic system[2]. In this compound several phase transitions occur at low temperatures. We present measurements of κ for different axes and magnetic fields, and find a highly unusual temperature dependence.

[1] T. Kimura et al., PRB 71, 224425 (2005).

[2] A.K. Zvedzdin et al., JETP 81, 272 (2005).

This work was supported by the DFG through SFB 608