Regensburg 2007 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 17: Magnetic Shape Memory Alloys

MA 17.12: Vortrag

Mittwoch, 28. März 2007, 18:00–18:15, H10

In-situ magnetic domain observation during twin boundary movement in bulk Ni-Mn-Ga — •Ryan Yiu Wai Lai, Jeffrey McCord, Nils Scheerbaum, Oliver Gutfleisch, Rudolf Schäfer, and Ludwig Schultz — Leibniz Institute for Solid State and Materials Research IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany

A study of twin boundary movement in a Ni-Mn-Ga single crystal in connection with in-situ magnetic domain observation is presented. Polarization microscopy in connection with a magneto-optical indicator film (MOIF) technique was used to record the magnetic domain pattern's reorganization during the process. A magnetic field up to 330 mT in amplitude was applied to a single variant sample with the structural c-axis being also the magnetically easy axis, aligned perpendicular to the field direction. Structural reorientation by twin boundary movement was induced by the magnetic field. Images at different field strength display no domain wall movement, even during twin boundary movement. This result is different from the previously proposed model, which assumes domain wall movement under an external field [1]. Funding through the DFG priority program SPP1239 is gratefully acknowledged. [1] H.E. Karaca et al. Acta Materialia 54 (2006) 233-245