A two-axis magnetometer using a single magnetic tunnel junction

Based on a qualitative study of the Stoner-Wohlfarth model, we point out that driving a magnetic tunnel junction (MTJ) with an alternative two-dimensional magnetic field allows to measure simultaneously two components of an external magnetic field. Only one single MTJ without a pinning layer is needed to measure both components of a magnetic field parallel to the junction plane. The response of the magnetometer does not depend on the resistance of the junction or the amplitude of its variations. A prototype has been manufactured and encouraging experimental results are presented. Sensitivities higher than 500 V/T and a noise level of 2 muT/rootHz are reported.