The inverse magnetic shape memory effect in membranes for pressure sensor applications

This paper presents the basis for a novel pressure sensor application based on the ferromagnetic shape memory alloy (FSMA) NiMnGa. Usually, the underlying mechanism for sensing applications using FSMAs is a martensitic reorientation accompanied by a change of magnetization. The magnetization change upon application of mechanical stress can be measured using a magnetic field sensor. We demonstrate that martensitic reorientations are detectable in pressurized membranes despite the complex distribution of mechanical stress arising in such geometries. Further, a change of magnetization within the FSMA membranes was detected using a giant magnetoresistance (GMR) sensor. The experimental results serve as a proof of concept for a membrane-based pressure sensor using FSMAs.