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) Ultrafast demagnetization curves for Co and Ni in Co/Ni bilayers with interfical coupling constant and . The inset shows the partial enlarged details of the main figure between 0.21 ps to 0.29 ps of time delay.