Dresden 2009 – scientific programme

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MA: Fachverband Magnetismus

MA 13: Poster Ia: Electron Theory (1); Magnetic Imaging (2,3); Thin Films (4-25); MSMA (26-33); Magn. Semiconductors (34-42); Magn. Half Metals and Oxides (43-60)

MA 13.28: Poster

Tuesday, March 24, 2009, 10:15–13:00, P1A

Composition and microstructure of sputtered Ni-Mn-Ga magnetic shape memory thin films — •J. Petersen, Y. Luo, S. G. Mayr, and K. Samwer — I. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen

Ni-Mn-Ga films close to the composition of Ni₅₀Mn₃₀Ga₂₀ were sputter deposited onto different substrates, e.g. thermally oxidized silicon and NaCl(100). Object to the investigation is the influence of deposition parameters on the resulting film composition, phase and microstructure. The Ni content of the original sputtering target (Ni₅₀Mn₃₀Ga₂₀) was increased to obtain a higher martensitic transformation temperature T_M above room temperature (here T_M > 150^∘C measured by temperature dependent x-ray diffraction). First results show a significant depletion of Mn in the films with increasing deposition temperature whereas the ratio of Ni to Ga remains nearly constant. While thermally annealed films deposited at room temperature show the same 7M modulated martensitic phase and depletion of Mn, the advantage is that loss of Mn can be limited by using short annealing times and surface roughness is dramatically reduced. We acknowledge support by the BMBF - project 13N10061 MSM-sens.