Spin torque gate magnetic field sensor

TL;DR

This paper introduces a simple, bias-free spin torque gate magnetic field sensor that operates linearly in the 3-10 Oe range, using a novel trilayer structure and ac driving to eliminate offset issues.

Contribution

It presents a new spin torque gate sensor design that simplifies structure and operation by removing the need for magnetic bias and compensation circuits.

Findings

Sensor operates linearly in 3-10 Oe range

No magnetic bias or compensation circuit needed

Demonstrated with WTe2/Ti/CoFeB trilayer

Abstract

Spin-orbit torque provides an efficient pathway to manipulate the magnetic state and magnetization dynamics of magnetic materials, which is crucial for energy-efficient operation of a variety of spintronic devices such as magnetic memory, logic, oscillator, and neuromorphic computing. Here, we describe and experimentally demonstrate a strategy for the realization of a spin torque gate magnetic field sensor with extremely simple structure by exploiting the longitudinal field dependence of the spin torque driven magnetization switching. Unlike most magnetoresistance sensors which require a delicate magnetic bias to achieve a linear response to the external field, the spin torque gate sensor can achieve the same without any magnetic bias, which greatly simplifies the sensor structure. Furthermore, by driving the sensor using an ac current, the dc offset is automatically suppressed, which eliminates the need for a bridge or compensation circuit. We verify the concept using the newly developed WTe2/Ti/CoFeB trilayer and demonstrate that the sensor can work linearly in the range of 3-10 Oe with negligible dc offset.