Anomalous Hall effect in an amorphous antiferromagnet with inverted hysteresis

Abstract: Stemming from antiferromagnetic coupling, exchange bias allows inverted hysteresis in a magnetic system. Such room temperature magnetic reversal has yet to be observed in an amorphous antiferromagnet. Furthermore, the impact of this exchange bias effect on its magnetoelectric transport behavior remains a mystery. Here we discovered a zero-field magnetization switching effect in an exchange-biased amorphous antiferromagnet with inverted magnetic hysteresis. This zero-field magnetic reversal was further evidenced by its inverted large anomalous Hall effect. Notably, this collective spin flipping at zero field can occur at room temperature or above room temperature, which may be associated with quantum interference effect due to thermal fluctuation enhanced disorder. Our experimental results offer a way to design room-temperature exchange-biased amorphous antiferromagnets with zero-field multi magnetic-states and large anomalous Hall effect, holding potential for low-power and high-density memory applications.