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 20.153: Poster
Dienstag, 28. März 2006, 15:15–19:15, P1
Growth of Ni2MnGa films on a-plane sapphire — •Gerhard Jakob and Hermann Adrian — Institute of Physics, Johannes Gutenberg-University of Mainz
Magnetic shape memory materials can change their shape on application of magnetic fields. Huge magnetostrictive effects as large as 10% have been achieved in Ni2MnGa single crystals [1]. The shape change is related to the fact that the energy for motion of twin boundaries in these materials is lower than the magneto crystalline anisotropy energy. Using an appropriate Ni-Mn ratio the martensitic formation temperature is above room temperature opening the potential for actuators based on this effect.
We report our results concerning growth and characterization of Ni2MnGa films deposited by sputtering on a-plane sapphire. Our samples grow with a (220) orientation and a rocking curve width of 1.1∘ for the out of plane orientation. Four circle diffractometry showed the presence of several competing in-plane growth directions. Magnetic measurements indicate the existence of the austenite martensite transformation in the films. Substrates suitable as sacrificing layers have been investigated.
[1] A. Sozinov et al, Appl. Phys. Lett. 80, 1746 (2002) We thank Dr. S. Roth from IFW Dresden for providing the target material.