Influence of Negative Field Cooling on the Exchange Bias Properties of Potassium Split Graphene Nanoribbons

Abstract

Abstract:We demonstrate the evidenced exchange bias properties of graphene nanoribbons (GNRs) with the negative magnetic field cooling. Upon the negative field cooling from 300 K to 5 K, the hysteresis loop shifts along the negative magnetic field axis, that coincides with the cooling field direction. This observation indicates that there exists a positive exchange bias in GNRs. Furthermore, enhanced exchange bias was observed when the polarity of field cooling is negative as compared with positive field cooling, hinting that there might be complex interplay between orbital and spin degrees of freedom. In addition, the variation of exchange bias and the coercive field as a function of negative cooling field is also studied.