Abstract
This paper reports the development of integrated micro-sensors consisting of 1 -mu m-thick magnetostrictive cantilevers or bridges with 500 mu m in length and conducting interrogation elements. The thin films are fabricated by sputter deposition of NiFe doped with B and Mo, and the magnetic properties are enhanced by field annealing, resulting in a coercivity of 2.4 Oe. In operation, an alternating current applied to the interrogation elements magnetizes the magnetostrictive structures. The longitudinal resonant frequency is detected as an impedance change of the interrogation elements. The magnetostrictive micro-beams provide high resonant frequencies-2.95 MHz for the cantilever and 5.46 MHz for the bridge-which can be exploited to develop sensors of high sensitivity. (C) 2012 American Institute of Physics. [doi:10.1063/1.3679016]