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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 20.140: Poster

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

Magnetic Phase Diagram of Paramagnetic Shape Memory Compounds — •W. Lorenz¹, M. Böttger¹, M. Dörr¹, S. Raasch¹, M. Rotter², and M. Loewenhaupt¹ — ¹Institut für Festkörperphysik, Technische Universität Dresden, D-01062 Dresden, Germany — ²Institut für Physikalische Chemie, Universität Wien, A-1090 Wien, Austria

Magnetostriction measurements on DyCu₂ and Tb_0.5Dy_0.5Cu₂ have been carried out in order to construct the magnetic phase diagrams. These data very well complement and support earlier magnetization measurements on these Rare Earth-Transition Metal compounds.

The RCu₂ compounds (R = Rare earth) order antiferromagnetically at low temperatures. In fact, these compounds have been the first for which magnetic shape memory effects (MSM) could be shown in the antiferromagnetic as well as in the paramagnetic state. The transition field of the irreversible transition into several variants is enhanced in the antiferromagnetic state. As these antiferromagnets show complex magnetic phase diagrams their investigation is promising fundamental insights into the physical mechanisms of the shape memory magnetostriction.

The magnetostriction measurements have been accomplished at low temperature and high static magnetic fields by means of capacitive dilatometry. This method allows high resolution measurement. Further evaluation of the data was performed using the mean-field Monte-Carlo simulation program McPhase (http://www.mcphase.de).