Measurement of magnetostriction coefficient λsλs by speckle photography

In this paper we present a general procedure based on the speckle photography to calculate both the longitudinal magnetostriction λs‖λs‖ and the transversal magnetostriction λs⊥λs⊥ in saturation, in only one experiment. For this purpose, we propose a model in which not only the deformation of the sample, but also its rigid movements are taken into consideration. To test the model, experimental results for nickel are reported, and a discussion of the uncertainty of the method is shown.