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In this study, a hysteresis reduction technique for tunneling magnetoresistive (TMR) sensor for low magnetic field sensing is proposed, where a small ac modulation magnetic field is applied. The magnetic tunnel junctions (MTJs) were connected into an asymmetric Wheatstone bridge to form a sensor, and the output voltage of the TMR sensor was measured using a small ac modulation field and test field along the sensor’s sensing direction. The results showed that hysteresis in the TMR sensor can be effectively reduced to exhibit a linear response. Further, the frequency response of the TMR sensor was studied. Finally, the feasibility of the TMR sensor for low-field detection with small ac modulation was demonstrated. [ABSTRACT FROM AUTHOR]

A simple and practical ac modulation method to reduce the hysteresis in tunneling magnetoresistive (TMR) sensor is demonstrated. It is shown that with a suitable ac modulation magnetic field that is applied along the sensing direction of the TMR sensor, the hysteresis in the sensor can be reduced to a negligible level. Also, depending on the amplitude of the modulation field, the sensitivity and the dynamic range of the TMR sensor can be tuned to meet practical requirements in specific applications. The influence of the modulation on the noise of TMR sensor is also studied. [ABSTRACT FROM AUTHOR]