Anomalous Spontaneous Reversal in Magnetic Heterostructures

This papers present a novel phenomenon in FM/AF heterostructure systems (AF = FeF2, FM= (Ni,Co)), where the FM switching can be also controlled by thermal cycling. It was found that a FM saturated above the AF Neel temperature TN, spontaneously reverses its magnetization against a constant field with decreasing temperature. This reversal also exhibits a significant magnetization vs. temperature hysteresis, with a tunable height and width by the field. This is reminiscent of the conventional magnetization hysteresis and enables one to control the FM switching by thermal cycles, and may have implication on the thermally assisted magnetic recording.