Room and Cryogenic Temperature Behaviour of Magnetic Sensors Based on Gan/Si Single Saw Resonators

Abstract

This work analyzes resonance frequency shift vs. the applied magnetic field strength for GHz operating GaN/Si SAW single resonators. Magnetostrictive elements (Ni and CoFeB) were deposited in the proximity of the interdigitated transducers (IDTs) of the resonators (A-type structures) and also over the IDTs, after covering them with a BCB layer to avoid short circuits with IDTs metal (B-type structures). This work targets emerging applications of SAW resonators in driving spin wave pumping and in coupling of surface acoustic waves (SAW) with superconducting Q-bits. Magnetic sensitivity of the SAWs was analyzed at room temperature (RT) and at cryogenic temperatures, obtaining high magnetic sensitivities at 16 K. According to our knowledge, GaN based SAWs are first time used in magnetic applications; also, cryogenic behavior of magnetic SAW sensors is first time analyzed.

Reversible response of a magnetic surface acoustic wave device with perpendicular magnetization

“…From the end of the seventies, magnetic surface acoustic wave systems have been proposed, based on the strain induced by a magnetostrictive materials [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Most of the research activities appear to focus on two main aspects: (i) the modification of the surface acoustic wave (SAW) characteristics (resonance, shape …) by an external static magnetic field [1][2][3][4][5][6][7][8][9][10][11] (ii) and the elastic excitation of the magnetization dynamics, i.e. SAWferromagnetic resonance (SAW-FMR) [12][13][14][15][16][17][18][19].…”