Interfacial effect on the reverse of magnetization and ultrafast demagnetization in Co/Ni bilayers with perpendicular magnetic anisotropy

Gong Zi-Zhao^{1, 2}, Zhang Wei^{2, 3}, He Wei², Zhang Xiang-Qun², Liu Yong^{1, †}, Cheng Zhao-Hua^{2, 3, ‡}

(color online) Calculated major hysteresis loops of the Co/Ni bilayers with out plane easy axes based on OOMMF with various interface exchange energy constants.