Optimizing magnetoresistive sensor signal-to-noise via pinning field tuning

TL;DR

This paper investigates methods to optimize magnetoresistive sensor performance by tuning the pinning field, demonstrating that combined approaches can significantly reduce magnetic noise and improve detection limits.

Contribution

It introduces and compares three pinning field methods, showing their equivalence and optimal combination for noise suppression in magnetoresistive sensors.

Findings

Detection limit improved up to tenfold

Optimal pinning field balances noise suppression and sensitivity

Methods are equivalent and can be combined

Abstract

The presence of magnetic noise in magnetoresistive-based magnetic sensors degrades their detection limit at low frequencies. In this paper, different ways of stabilizing the magnetic sensing layer to suppress magnetic noise are investigated by applying a pinning field, either by an external field, internally in the stack or by shape anisotropy. We show that these three methods are equivalent, could be combined and that there is a competition between noise suppression and sensitivity reduction, which results in an optimum total pinning field, for which the detection limit of the sensor is improved up to a factor of ten.