Measurement of very low magnetostrictions in thin films

A highly sensitive optical interferometer with in-situ calibration was developed to measure the low-field magnetostriction of magnetic thin films using the cantilever beam technique, The high displacement resolution (0.01 /spl Aring/) of this instrument permits the measurement of magnetostrictions of 10/sup -9/. First measurements on a soft CoFeSiB thin film were made to demonstrate this technique. The magnetostriction measurement resolution of 5/spl times/10 obtained is the lowest yet reported value. The dynamic range of the technique was demonstrated in measurements of a magnetostriction greater than 10/sup -5/.