Lattice mismatch induced weak perpendicular anisotropy in Fe/Co multilayers prepared by direct current magnetron sputtering

We presented a magnetic force microscopy and vibrating sample magnetometer study of perpendicular anisotropy of [Cot/Fe3t]5 (t = 2, 3, 4, 5 nm) multilayers prepared by direct current magnetron sputtering on glass and Si substrates. It was found that except for the specimens with t = 2 nm, most specimens exhibited obvious weak perpendicular anisotropy. By analyzing the anisotropy field and the root-mean-square roughness of phase shift of magnetic force images, we compared the perpendicular anisotropy among the multilayers deposited on Si and glass substrates. As a result, it is concluded that the primary origin of the weak perpendicular anisotropy can be attributed to the compressive stress induced by the lattice mismatch between Fe and Co layers.