Dresden 2006 – wissenschaftliches Programm

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MA: Magnetismus

MA 20: Poster: Films(1-36) Transp(37-56) Ex.Bias(57-67) Spindyn(68-80) Micromag(81-95) Particle(96-109) Imag.+Surface(110-113) Spinelectr(114-122) Theory+Micromag(123-131) Spinstr+Aniso(132-142) MagMat(143-156) Meas(157,158) MolMag+Kondo(159-162) Postdead(163-)

MA 20.141: Poster

Dienstag, 28. März 2006, 15:15–19:15, P1

Pulsed laser deposition of epitaxial Fe_70+xPd_30−x magnetic shape memory films — •Jörg Buschbeck, Martin Weisheit, Sebastian Fähler, and Ludwig Schultz — IFW Dresden, Institute for Metallic Materials, P.O. Box 270116, D-01171 Dresden, Germany

Magnetic shape memory materials like Ni-Mn-Ga and Fe₇₀Pd₃₀ reach high strains in a moderate applied magnetic field below 1 T due to a selective growth of martensite variants. Though the maximum strain is limited to about 5%, Fe₇₀Pd₃₀ films 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. First, to study their basic properties, Fe_70+xPd_30−x films are deposited by Pulsed Laser Deposition in UHV of p=10⁻⁹ mbar. It is observed, that films grow (100) epitaxially on MgO (100) substrates. Depending on the films composition (x= − 10...+10), the bcc or fcc structure is observed in the as deposited state. Annealing experiments are carried out to transform the films into the martensitic phase. In order to allow an easy movement of twin boundaries required for a high strain free standing films are required. To achieve this, sacrificial buffer layers are used and dissolved to lift off the film from the substrate. Phase transformation and texture are analysed by x-ray diffraction measurements ( θ−2θ , texture) and temperature dependent magnetic measurements are used to examine phase transformations.