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MM: Fachverband Metall- und Materialphysik
MM 6: Microstructure and Phase Transformations I - Martensitic phase transformations
MM 6.3: Vortrag
Montag, 31. März 2014, 10:45–11:00, IFW B
Laser annealing of Fe7Pd3 ferromagnetic shape memory thin films — •Ariyan Arabi-Hashemi1, Martin Ehrhardt1, Pierre Lorenz1, Dietmar Hirsch1, Klaus Zimmer1, and Stefan G. Mayr1,2,3 — 1Leibniz-Institut für Oberflächenmodifizierung e.V., Permoserstraße 15, 04318 Leipzig, Germany — 2Translationszentrum für regenerative Medizin, Universität Leipzig, 04103 Leipzig, Germany — 3Fakultät für Physik und Geowissenschaften, Universität Leipzig, 04103 Leipzig, Germany
Fe7Pd3 is a magnetic shape memory alloy capable of performing strains of up to 5% by applying an external magnetic field. While the austenite phase of Fe7Pd3 is fcc, the martensite phases are fct, bct and bcc. The magnetic shape memory effect is only observed in the fct phase due to a high magnetocrystalline anisotropy and a high mobility of twin boundaries. We study phase transformation effects in Fe7Pd3 films annealed by 25 ns pulses of a KrF laser for various substrates: LaSrAlTaO, MgO and Si. The laser-solid interaction was simulated by finite element method. Laser annealing experiments are compared with thermal annealing experiments. Low temperature electron beam evaporation deposited samples reside in the bcc phase independently of the used substrate. Subsequent laser and thermal annealing of Fe7Pd3 films deposited on MgO reside in the bcc phase, while laser annealed Fe7Pd3 films on LSAT show a phase transformation from bcc to fcc. In thermally annealed Fe7Pd3 on LSAT fcc and fct is observed. Interdiffusion was studied by SIMS.