Comparison of Sensitivity and Low Frequency Noise Contributions in GMR and TMR Spin Valve Sensors with a Vortex State Free Layer

TL;DR

This paper compares GMR and TMR spin valve sensors with vortex state free layers, focusing on sensitivity and low frequency noise, revealing trade-offs in noise, linearity, and sensitivity for different applications.

Contribution

It provides a direct comparison of GMR and TMR sensors with vortex free layers, highlighting their respective noise characteristics and sensitivity performance.

Findings

GMR sensors exhibit lower pink noise and better linearity.

TMR sensors have higher sensitivity to external magnetic fields.

Both sensors show comparable detectivity at low frequencies.

Abstract

Magnetoresistive spin valve sensors based on the giant- (GMR) and tunnelling- (TMR) magnetoresisitve effect with a flux-closed vortex state free layer design are compared by means of sensitivity and low frequency noise. The vortex state free layer enables high saturation fields with negligible hysteresis, making it attractive for applications with a high dynamic range. The measured GMR devices comprise lower pink noise and better linearity in resistance but are less sensitive to external magnetic fields than TMR sensors. The results show a comparable detectivity at low frequencies and a better performance of the TMR minimum detectable field at frequencies in the white noise limit.