Observation of thin film magnetostriction using a piezoelectric sensor

A cantilevered glass substrate with a magnetic thin film deposited on one side vibrates under an alternating magnetic field applied parallel to the film surface. The vibration amplitude, which is proportional to magnetostriction constant of the film, is measured with a bimorph piezoelectric sensor. The magnetostriction of such a film can be calculated from the vibration amplitude, elastic modulus and geometry of the sample. The generated electrostatic charge is proportional to the amplitude in the sensor and measured using an analog integrator, which is also an effective noise suppressor. The instrument is calibrated with a Ni film as the standard