Regensburg 2007 – scientific programme

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MA: Fachverband Magnetismus

MA 17: Magnetic Shape Memory Alloys

MA 17.11: Talk

Wednesday, March 28, 2007, 17:45–18:00, H10

Epitaxial growth of martensitic Ni-Mn-Ga films prepared by sputter deposition — •Michael Thomas, Jörg Buschbeck, Oleg Heczko, Ludwig Schultz, and Sebastian Fähler — IFW Dresden, Helmholtzstraße 20, 01069 Dresden

Bulk Ni-Mn-Ga material exhibits a large magnetic-field-induced strain up to 6% in the 5M phase and 10% in the 7M phase. While the phenomenology and requirements in bulk single crystals are understood quite well, only little work has been done on thin films until now. Ni-Mn-Ga films were deposited on MgO, Al₂O₃, SrTiO₃, NaCl and Si single crystals with different orientations under variation of the deposition temperature by DC sputtering. The estimated film thickness was about 650 nm. The samples were analyzed with XRD using 2θ and pole figure measurements. At certain deposition conditions an epitaxial growth occured. A martensitic phase was observed on MgO, SrTiO₃ and NaCl substrates at room temperature. The influence of substrate symmetry and misfit between the substrate and the Ni-Mn-Ga films on the existence of martensitic phase and martensitic variant orientation is discussed. This work is supported by the SPP 1239, project C3 (http://www.magneticshape.de).