Wide range and tunable linear TMR sensor using two exchange pinned electrodes

TL;DR

This paper introduces a tunable linear TMR sensor with exchange pinned electrodes, leveraging IrMn layers with different blocking temperatures to achieve adjustable sensitivity and linear range.

Contribution

It presents a novel magnetic tunnel junction sensor design with tunable sensitivity and linearity using crossed anisotropies induced by IrMn layers of varying thickness.

Findings

Sensitivity varies linearly with ferromagnetic thickness.

Increasing detection electrode thickness enhances sensitivity.

Thicker electrodes reduce the sensor's linear operating range.

Abstract

A magnetic tunnel junction sensor is proposed, with both the detection and the reference layers pinned by IrMn. Using the differences in the blocking temperatures of the IrMn films with different thicknesses, crossed anisotropies can be induced between the detection and the reference electrodes. The pinning of the sensing electrode ensures a linear and reversible output. It also allows tuning both the sensitivity and the linear range of the sensor. The authors show that the sensitivity varies linearly with the ferromagnetic thickness of the detection electrode. It is demonstrated that an increased thickness leads to a rise of sensitivity and a reduction of the operating range.