Magnetoelastic microtransformer with improved core design

In a thin film microtransformer with a magnetostrictive core, the amount of coupling between the two transformer coils depends on the strain the core is exposed to. Therefore. such a microtransformer lends itself to be used as a micro strain gauge [I] and is an attractive alternative to both classic metal strain gauges as well as piezoresistive devices. For metal strain gauges. the sensor‘s sensitivity factor k is in the order of 2 and for piezoresistive strain gauges it is around 100. For magnetoelastic microtransformers, an at least ten times higher sensitivity seems to be achievable. This paper investigates how the sensitivity of such a device may be optimized by varying both the design as well as the material of the microtransformer’s core.