Suppression of martensitic phase transition at the Ni2 MnGa film surface

Publication Type:

Journal Article

Source:

Applied Physics Letters, Volume 93, Number 2 (2008)

Abstract:

We investigated magnetic and structural properties at the surface of epitaxial Ni2 MnGa (110) Heusler films using x-ray absorption spectroscopy and x-ray magnetic circular dichroism both in transmission and total electron yield mode. The magnetic shape memory films were prepared by dc sputtering from a stoichiometric target onto sapphire substrates at an optimized substrate temperature of 773 K. X-ray diffraction confirms a (110) oriented growth on Al2 O3 (11 2- 0) and an austenite to martensite transition at 270-280 K. At the surface the martensitic phase transition and the magnetization are strongly suppressed. The deviation in the surface properties is caused by a Mn deficiency near the surface. © 2008 American Institute of Physics.

Notes:

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