BCMaterials´ first paper published at Applied Physics Letters

Applied Physics Letters has published BCMaterials first scientific paper "Transformation volume strain in Ni-Mn-Ga thin films"  I. R. Aseguinolaza,1 I. Reyes-Salazar,1 A. V. Svalov,1 K. Wilson,2 W. B. Knowlton,2 P. M€ullner,2 J. M. Barandiaran,1 E. Villa,3 and V. A. Chernenko1,4,a) 1BCMaterials and Department of Electricity and Electronics, University of the Basque Country (UPV/EHU),P.O. Box 644, Bilbao 48080, Spain 2Department of Materials Science and Engineering, Boise State University, Boise, Idaho 83725, USA 3CNR-IENI, C.Promessi Sposi, 29, Lecco 23900, Italy 4Ikerbasque, Basque Foundation for Science, Bilbao 48011, Spain

Abstract:

The temperature dependences of the lattice parameters and residual stress have been measured for a fine-grained Ni52.2Mn26.8Ga21.0   (at. %) thin film fabricated by sputter deposition onto a heated silicon wafer with SiNx  buffer layer.  The transformation volume strain in the film was found to be a lattice expansion during the forward martensitic transformation which is opposite to a volume contraction exhibited by bulk Ni-Mn-Ga alloys. This unusual effect can be explained by the substrate-induced residual stresses in the film and the difference in the elastic modulus of austenite and martensite. © 2012

American Institute of Physics. [http://dx.doi.org/10.1063/1.4772005]