Regensburg 2007 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 17: Magnetic Shape Memory Alloys

MA 17.16: Vortrag

Mittwoch, 28. März 2007, 19:00–19:15, H10

Epitaxial Growth, Structure and Magnetic Properties of Fe-Pd films — •Jörg Buschbeck, Inge Lindemann, Ludwig Schultz, and Sebastian Fähler — IFW Dresden, Institute for Metallic Materials, P.O. Box: 270116, 01171 Dresden, Germany

Magnetic shape memory materials like Ni-Mn-Ga and Fe-Pd reach high strains in moderate applied magnetic fields below 1 T due to a selective growth of martensite variants. The maximum strain of Fe70Pd30 is about 3%. Films of this material are interesting candidates for micro-actuators and sensors, because of the materials high ductility and the ability to compensate internal stresses during the straining process. Fe(70+x)Pd(30-x) films are deposited by Pulsed Laser Deposition in UHV of p=10^(-9) mbar at room temperature. It is observed, that the films grow (100) epitaxially on MgO (100) substrates. XRD measurements indicate martensitic phase formation in the films. In the as-depositied state the metastable phases change from fct to bct and bcc when reducing the Pd content. Temperature dependent magnetic measurements indicate a transition occurring in the fct phase. It is suggested that in the films stress induced martensite formation occurs. Furthermore annealing experiments are carried out. After annealing, the films are relaxed and instead of the fct phase the fcc phase is observed in X-ray measurements on Pd-rich films (X<0).