The magnetostriction constant λS of a magnetic film is usually measured by detecting the mechanical distortion of the film deposited on a thin glass substrate under an applied field using a laser beam. This method, however, cannot be applied to a film deposited on a rigid substrate such as Si and AlTiC used widely in real-world application. This is because that the distortion of the sample is too small to be detected. In addition, λS of the film deposited on the glass substrate sometimes differ from those of the film deposited on the Si or AlTiC substrate. Thus, it is very important to evaluate λS of a film deposited on an actual substrate. In this paper, a new method for measuring λS of a film deposited on a substrate used in actual products is proposed by detecting the change of the anisotropic field Hk of the film under bending load. λS can be calculated from the gradient of the applied mechanical stress dependence of the HK. Utilizing this method, we have successfully measured λS of GMR films fabricated on the practical substrate by a very high resolution of 2×10-8.
ASJC Scopus subject areas
- Physics and Astronomy(all)