Regensburg 2010 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
MA: Fachverband Magnetismus
MA 8: Magnetic Shape Memory Alloys
MA 8.9: Vortrag
Montag, 22. März 2010, 17:15–17:30, H22
A comparison of substrate-constraint and freestanding thin Ni-Mn-Ga films — •Anja Backen1,2, Srinivasa Yeduru Reddy3, Manfred Kohl3, Anett Diestel1,2, Ludwig Schultz1,2, and Sebastian Faehler1 — 1IFW Dresden, Institute for Metallic Materials, P.O. Box 270116, 01171 Dresden, Germany — 2Dresden University of Technology, Department of Mechanical Engineering, Institute of Materials Science, 01062 Dresden, Germany — 3Karlsruhe Institute of Technology, Institute of Microstructure Technology, Herrmann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
The magnetic shape memory alloy Ni-Mn-Ga belongs to a class of active materials where an external magnetic field can cause a maximum strain of 10 % in bulk single crystals. In order to use this effect for microsystems, scaling down from bulk dimensions is a key issue and thus epitaxial thin films are of particular interest. Recently we have reported on epitaxial growth of Ni-Mn-Ga on single crystalline MgO (100) substrates, however, the substrate constraints hinder elongation by magnetically induced reorientation. Hence, it is crucial to release films from the substrates. We report on successfully releasing thin Ni-Mn-Ga films grown on MgO (100) by using Chromium as sacrificial layer. We observe epitaxial growth of both Cr on MgO (100) and Ni-Mn-Ga on Cr without interdiffusion. After deposition, Cr can be etched selectively without affecting the Ni-Mn-Ga film properties. In order to understand the influence of substrate constraint on the film properties, structure, microstructure and magnetic properties are analyzed and compared for films before and after their release.