An accurate measurement of magnetostriction of thin films by using nano-indentation system

We have constructed a simple and sensitive tool for the measurement of magnetostriction of thin films. This tool is based on a commercial nano-indentation system, which enable the measurement of the elastic properties of small samples, such as thin films and precipitates, as well as the magnetostrictively induced deflection of cantilevered substrates on which thin film are deposited. The reliability of the present tool is tested by measuring Permalloy thin films. The resolution of the displacement is estimated to be less than 1 nm. Combined with an accurate determination of Young's modulus, the present system appears suitable to measure magnetostriction down to 10/sup -7/, if a 1 /spl mu/m thick film coated on a 0.3 mm thick film is used.