Hall effect spintronics for gas detection

TL;DR

This paper introduces a magnetic gas detection method using the Extraordinary Hall effect, enabling sensitive, simultaneous measurement of resistivity and magnetization changes caused by gases, demonstrated with hydrogen detection using CoPd films.

Contribution

It proposes a novel magnetic sensing technique for gas detection that surpasses traditional conductance methods in sensitivity and provides dual-parameter measurement capabilities.

Findings

Hall effect sensitivity exceeds 240% per 10^4 ppm for hydrogen

Detection sensitivity is over 100 times higher than conductance methods

Feasibility demonstrated with low concentration hydrogen detection

Abstract

We present the concept of magnetic gas detection by the Extraordinary Hall effect (EHE). The technique is compatible with the existing conductometric gas detection technologies and allows simultaneous measurement of two independent parameters: resistivity and magnetization affected by the target gas. Feasibility of the approach is demonstrated by detecting low concentration hydrogen using thin CoPd films as the sensor material. The Hall effect sensitivity of the optimized samples exceeds 240% per 104 ppm at hydrogen concentrations below 0.5% in the hydrogen/nitrogen atmosphere, which is more than two orders of magnitude higher than the sensitivity of the conductance detection.