Magnetic field sensors using VO₂/Fe₃O₄ nanoparticle devices ^*

Abstract

We combined the metal-insulator transition (MIT) properties of VO2 and the magnetic properties of Fe3O4 to realize a magnetometer with very large non-linearity and switching characteristics. VO2, Fe3O4 nanoparticles, and a conductive binder (silver paint) were mixed and drop-casted onto two-terminal gap junction devices. The device current-voltage characteristics exhibited current-switching behavior related to MIT in VO2 which changed with the external magnetic field. The magnetoresistance and magnetostriction in Fe3O4 both contributed to the field sensitivity of the sensor. Sensitivities as high as 1 A/nT (or 50.8 V/T with a current bias) were observed near the MIT voltage. The resulting minimum detectable signal was 20 pT/SQRT(Hz).

Data Access
Statement: All relevant data are within the paper.