Elastic modulus measurement of thin films coated onto magnetoelastic ribbons

A model is presented to describe the change of the resonant frequency of a magnetoelastic sensor when the sensor is coated with a material of given el asticity. With a mass load coated on the surface of the sensor, its charact eristic resonant frequency changes depending on the ratio of the sound velo cities in the sensor and the coating. A measurement technique is derived th at allows the determination of Young's modulus of elasticity of thin film c oatings, with thickness greater than approximately 75 nm, based on the meas urement of mass and resonant frequency of a sensor before and after coating . Comparing the measurement to the model delivers the value of Young's modu lus of elasticity for a coating of known density.