Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 17: Magnetic Shape Memory Alloys
MA 17.13: Vortrag
Mittwoch, 28. März 2007, 18:15–18:30, H10
Controlling the martensitic transformation temperature at constant valence electron concentration in Heusler based Ni-Mn-In alloys — •Seda Aksoy1, Mehmet Acet1, Thorsten Krenke1, Eberhard Wassermann1, Xavier Moya2, Lluis Manosa2, and Antoni Planes2 — 1Experimentalphysik (AGFarle), Universitaet Duisburg-Essen, 47048 Duisburg — 2Departament d'Estructura i Constituents de la Materia, Facultat de Fisica, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona
Although the martensitic transformation temperature Ms increases linearly with increasing valence electron concentration e/a in Ni-Mn-X Heusler alloys (X: group III or IV element), the slope varies depending on the X-species, i.e., Ms vs. e/a is not universal. This aspect can be favorably exploited to control Ms by holding e/a constant and replacing X by an isoelectronic X*, where X and X* are elements within the same group. Using this property we have substituted In in Ni50Mn34In16 (Ms~200 K) with Ga to bring Ms close to room temperature. Here, we show how magnetic field induced phase transition properties and associated magnetocaloric effects in Ni50Mn34In16 are modified in Ni50Mn34(In,Ga)16.