Comparison of hysteresis loop area scaling behavior of Co/Pt multilayers: Discrete and continuous field sweeping

Abstract

We have investigated the hysteresis loop shape changes with discrete and continuous magnetic field sweeping for Co/Pt multilayers with a perpendicular magnetic anisotropy. The hysteresis loop shape was observed by measuring a polar magneto-optical Kerr effect. The loop area has been found to increase rapidly with an increase of the field step size as well as the sweeping frequency until the area reaches a maximum. The increase of the loop area has been analyzed based on the Steinmetz law, where a loop area scaling exponent determined from discrete field sweeping is compared to a scaling exponent from continuous field sweeping. The dynamic coercivity behavior with respect to discrete and continuous field sweeping is analyzed together with the loop area scaling behavior, suggesting that details of magnetic configuration disorders do not modify the loop area scaling exponent.