Design of three-dimensional magnetic field sensor with single bridge of spin-valve giant magnetoresistance films

Abstract

Nowadays, many applications of magnetic sensing such as automotive, electronics, electrical, and navigation applications impose increasing demand for the vector magnetometer The required specifications, e g for the electronic compass, are low power consumption, low cost, high detectivity, linearity, and 3-dimensional (3D) measurement ability. In recent decades, several techniques to implement the monolithic magnetometer capable of 3D detection have been reported in several different methods [1]-[6], e g three-axis Hall magnetometer [1-3], the anisotropic magnetoresistance (AMR) effect onto the V-groove substrates to detect the z-axis field component [4] or dualbridge giant magnetoresistance (GMR) sensor in-plane with a flux-guide [6]. The basic way to build a vector magnetometer, using solid-state sensors [3], [5], [6], is to align three individual sensors with orthogonal sensing directions [5]. However, all of above reports used at least three Wheatstone-bridge sensors to form a vector magnetometer. In this work, we design and manufacture a 3D GMR magnetic field sensor with only a single-bridge and a flux-guide. The proposed design helps reducing the sensor size, power consumption, and fabrication cost. The test results of a prototype single-bridge 3D magnetic field sensor were demonstrated and discussed.