Magnetostriction measurement by interferometry

A laser Doppler interferometric method using synchronous detection to measure the magnetostriction of soft magnetic films is described. The instrument measures 2 AA magnetostrictive deflections of Permalloy films on 500 mu m silicon substrates. Saturation magnetostriction of 10/sup -9/ can be measured for 1000 nm films on 100 mu m Si substrates. The ultimate resolution of the interferometer is 0.1 AA as demonstrated using piezoelectrically-driven mirrors.<
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