Magneto-piezoresistive elastomers optimization and sensitivity in prospect of MEMS using magnetization direction reading

The topic of magnetic elastomers and their properties was reorganized to clarify the host of elastomagnetic effects useful to explain the basic principles of magnetopiezoresistivity in micro-structured materials composed of magnetic particles homogeneously dispersed in an elastomer matrix. The working mechanism of the magnetopiezoresistive sensors is clarified and new results depending on the particle shape and preorientation are reported. A 20% improvement in sensor sensitivity for detecting magnetic field direction is experimentally demonstrated and qualitatively explained. The performances and limits of an optimized prototype sensor, to detect a random sequence of magnetic poles, have been investigated as a function of both the polar magnetization intensity and the poles sequence velocity. Concrete perspectives for application in MEMS devices are deduced.