Berlin 2015 – scientific programme
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MA: Fachverband Magnetismus
MA 51: Magnetic Shape Memory Alloys (Joint Session with MM)
MA 51.7: Talk
Friday, March 20, 2015, 11:00–11:15, H 0112
Study of magneto-elastic properties in shape-memory Heusler alloys by resonant ultrasound spectroscopy — •Catalina Salazar Mejia1, Ajaya K. Nayak1, Claudia Felser1, Michael Nicklas1, Jason Schiemer2, and Michael A. Carpenter2 — 1Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany — 2Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
Resonant ultrasound spectroscopy (RUS) is a versatile technique in materials science for measuring elastic constants. We have applied RUS to study the magneto-elastic properties in Heusler alloys. Heusler alloys that undergo a martensitic transformation (MT) have been shown to exhibit diverse functional properties such as the shape memory effect, magnetic-driven superelasticity and giant magnetocaloric and barocaloric effects, which derive from magnetoelastic couplings. The study of the magneto-elastic properties in these materials is important both from fundamental and the application points of view. We have studied polycrystalline Heusler alloys from the Ni-Mn-Ga and Ni-Mn-In families, in a temperature range that include the ferromagnetic and the martensitic transitions. We have observed fundamental differences in the behavior of the crystal lattice at the martensitic transition, i.e., stiffening versus softening, determined by the presence or absence of a pre-martensitic transition and the relation between the Curie temperature and the MT temperature. We will discuss these results in connection with magnetization and calorimetric data.