The capability of showing large magnetically induced strains (MFIS) up to about 10% has attracted considerable research interest to magnetic shape memory (MSM) alloys. The prototype MSM alloy was the ternary Ni2MnGa. In this work, a comprehensive study of the local unit cell orientation distribution on single crystalline, polycrystalline and epitaxial thin film of martensitic Ni2MnGa was conducted by electron backscattering diffraction. By electron back-scattering diffraction, the constraint-dependent twin variant distribution, the corresponding stresses and the three-dimensional orientation of twin planes will be investigated. In polycrystals, the differentiation between twin and grain boundaries as well as proof of twin boundary motion was shown. From the knowledge of the local unit cell orientation at surfaces, it was possible to explain the magnetic domain configuration imaged by magnetic force microscopy.

Constraint-Dependent Twin Variant Distribution in Ni2MnGa Single Crystal, Polycrystals and Thin Film - an EBSD Study. N.Scheerbaum, Y.W.Lai, T.Leisegang, M.Thomas, J.Liu, K.Khlopkov, J.McCord, S.Fähler, R.Träger, D.C.Meyer, L.Schultz, O.Gutfleisch: Acta Materialia, 2010, 58[14], 4629-38