Magnetic field sensor with voltage-tunable sensing properties

TL;DR

This paper introduces a voltage-tunable magnetic field sensor using CoFeB/MgO/CoFeB tunnel junctions, enabling active control of sensitivity and range through bias voltage adjustments.

Contribution

The study demonstrates a novel voltage-controlled tuning mechanism for magnetic sensor sensitivity and range in magnetic tunnel junctions.

Findings

Sensitivity increased by a factor of two.

Magnetic field operating range decreased by a factor of two.

Voltage bias effectively controls sensor properties.

Abstract

We report on a magnetic field sensor based on CoFeB/MgO/CoFeB magnetic tunnel junctions. By taking advantage of the perpendicular magnetic anisotropy of the CoFeB/MgO interface, the magnetization of the sensing layer is tilted out-of-plane which results in a linear response to in-plane magnetic fields. The application of a bias voltage across the MgO tunnel barrier of the field sensor affects the magnetic anisotropy and thereby its sensing properties. An increase of the maximum sensitivity and simultaneous decrease of the magnetic field operating range by a factor of two is measured. Based on these results, we propose a voltage-tunable sensor design that allows for active control of the sensitivity and the operating filed range with the strength and polarity of the applied bias voltage.