1/f noise of a tiny tunnel magnetoresistance sensor originated from a wide distribution of bath correlation time

TL;DR

This paper models 1/f noise in tiny TMR sensors using a macrospin approach, revealing a smaller Hooge parameter than larger sensors, which offers insights for noise reduction and sensor enhancement.

Contribution

It introduces a theoretical framework for 1/f noise in tiny TMR sensors, showing a reduced Hooge parameter due to a wide distribution of bath correlation times.

Findings

The Hooge parameter of tiny TMR sensors is significantly smaller than that of larger sensors.

Theoretical derivation of 1/f noise power spectrum from the generalized Langevin equation.

Provides new insights into magnetic 1/f noise mechanisms for sensor improvement.

Abstract

Tunnel magnetoresistance (TMR) sensor is a highly sensitive magnetic field sensor and is expected to be applied in various fields, such as magnetic recording, industrial sensing, and bio-medical sensing. To improve the detection capability of TMR sensors in low frequency regime it is necessary to suppress the 1/f noise. We theoretically study 1/f noise of a tiny TMR sensor using the macrospin model. Starting from the generalized Langevin equation, 1/f noise power spectrum and the Hooge parameter are derived. The calculated Hooge parameter of a tiny TMR sensor is much smaller than that of a conventional TMR sensor with large junction area. The results provide a new perspective on magnetic 1/f noise and will be useful for improvement of TMR sensors.