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MA: Fachverband Magnetismus
MA 21: Magnetic Materials
MA 21.8: Talk
Wednesday, March 24, 2010, 17:15–17:30, H23
Magnetic measurements on Tb5Ge3 — •Ariane Haase1,2, Mathias Doerr2, Marek Bartkowiak1, Ramzy Daou1,3, Yurii Skourski1, Martin Rotter4, and Marc Uhlarz1 — 1Hochfeld-Magnetlabor Dresden, Forschungszentrum Dresden-Rossendorf, 01314 Dresden — 2Institut für Festkörperphysik, TU Dresden, 01069 Dresden — 3Max-Planck-Institut für Chemische Physik fester Stoffe, 01187 Dresden — 4University of Oxford, Department of Physics, Oxford OX1 3PU
Tb5Ge3 is a weak antiferromagnet, which orders at 83 K. It crystallizes in Mn5Si3-type hexagonal structure with two different positions for the Tb3+ ions. The hexagonal ab-plane is the easy plane of magnetization.
Magnetization and magnetostriction measurements have been done on a single crystal in static fields up to 30 T and in pulsed fields up to 50 T. In addition to the antiferromagnetic phase, three more phases were found in fields in the ab-plane at low temperatures. Surprisingly, the measurements along the b-axis do not resemble the a-axis properties which indicates an anisotropy in the hexagonal plane. Initial model calculations reveal the anisotropy of the magnetic exchange, which is dominant over the crystal electric field effect, as cause. The hard c-axis shows only one phase transition at 5 T followed by a nearly linear magnetization and magnetostriction slope which is attributed to a steady-going rotation of the moment.