MEMS resonators actuated by TbCo/FeCo nanostructed magnetostrictive multilayers in liquid environment

This paper presents a novel type of remotely actuated, chemical or bio-sensor based on a MEMS resonator actuated by a multilayered (TbCo/FeCo) x25 nanostructured magnetostrictive film in liquid environment. The active film is polarized in order to induce spin reorientation transition, yielding giant sensitivity to a dynamical actuation magnetic field. Moreover, the resonator is placed at the air/liquid interface in order to increase its quality factor. Sensing results in different viscosity solutions are presented. The possibility to use such a device for the fast determination of cellular density is also demonstrated.