Sensitivity of Surface Acoustic Wave Magnetic Sensors Composed of Various Ni Electrode Structures

Abstract

A shear horizontal type of surface acoustic wave (SAW) magnetic sensor composed of a magnetostrictive Ni electrode and an ST-cut 90°X quartz substrate was fabricated. In this study, in order to obtain a higher magnetic sensitivity, one-port SAW resonators composed of three kinds of Ni electrode structures on the ST-cut 90°X quartz, namely, (a) grooved Ni electrodes, (b) additional overlaid Ni films on grooved Ni electrodes, and (c) Ni electrodes on the quartz, were fabricated and measured. In addition to these, a SAW resonator composed of a magnetostrictive TbFe2 film electrode, which has a larger magnetostrictivity than the Ni film, on the ST-cut 90°X quartz was also fabricated. Their characteristics are examined.