Position dependent inductance based on magnetic shape memory materials

Magnetic shape memory (MSM) materials provide a new way to produce motion and force. The material has also another interesting property: it is possible to monitor its shape by measuring its magnetic parameters. Based on this property, sensors and power generators can be made from the material. In this paper a new method for position sensing using MSM material is introduced and demonstrated. The size of an MSM element is changed in the air-gap of an inductor and the inductor's inductance is measured to see its dependence on the strain of the material. The physical background of the achieved signal is explained and a simple analytical formula for calculating the inductance as a function of the position is proposed. The calculated results are compared with the measured ones.