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MA: Fachverband Magnetismus

MA 25: Magnetic Shape Memory Alloys II (jointly with MM)

MA 25.5: Vortrag

Dienstag, 15. März 2011, 14:30–14:45, HSZ 103

Electronic structure, magnetic and transport properties of the Heusler shape memory alloy Mn₂NiGa. — •C. G. F. Blum^{1, 2}, S. Ouardi¹, G.H. Fecher¹, S. Wurmehl², B. Buechner², B. Balke¹, S. Ueda³, K. Kobayashi³, and C. Felser¹ — ¹Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg - University, Mainz, Germany — ²Institute of Solid State Research, IFW Dresden, D-01171 Dresden, Germany. — ³NIMS Beamline Station at SPring-8,National Institute for Materials Science, Hyogo 679-5148, Japan.

Magnetic shape memory based on Heusler compounds have received increasing interest, due their potential use for actuator and sensor applications. The single crystals Mn₂NiGa were grown by the optical floating zone method using a image furnace with vertical setup under a purified argon atmosphere. The both cubic (austenite) and tetragonal (martensite) phases of the sample were determined using temperature dependence powder x-ray diffraction XRD. The effect of martensitic transitions on the magnetic and transport properties of the compound was investigated by measuring the saturation magnetization, electrical resistivity ρ(T), the Seebeck coefficient S(T) and magnetoresistance R_M. All measurements detect clear signatures of the martensitic transition around room temperature with a thermal hysteresis up to 30 K. The electronic structures of the martensitic as well the austenitic phase were investigated using bulk-sensitive hard X-ray photoelectron spectroscopy (HAXPES).