Magnetic field sensor based on asymmetric inverse Wiedemann effect

A new type of magnetic field sensor is introduced. The sensor is based on asymmetric inverse Wiedemann effect in amorphous Co-rich ribbon with helical magnetic anisotropy induced by torque strain. The characterization of the stand-alone sensor and further the sensor with developed electronics for feedback operation was accomplished. Linear response of the sensor without feedback appears in narrow magnetic field range of +/- 15 mu T. For the feedback-loop connection the dynamic range has been enlarged up to +/-120 mu T. The linearity error FSR in the feedback connection is lower than 0.1% in the range of +/-75 mu T. The results show that the tested prototype achieves better stability than GMI sensors. The temperature offset drift, measured in temperature range of -20 degrees C to + 80 degrees C, is lower than 5 nT/K or -28 nT/K for the sensor operated with laboratory instruments only or with the developed simple electronics, respectively. For the magnetometer with sensor operating in the feedback loop the RMS noise of 80 pT was achieved in the frequency range from 30 mHz to 10 Hz. (C) 2007 Elsevier B.V. All rights reserved.