Magnetic textures and perpendicular anisotropy in asymmetric multilayers with Ta and W

Asymmetric (Pt/Co/X) multilayers where X is Ta or W have been investigated. Both structures showed a tailed hysteresis loop indicating the existence of skyrmions. The interfacial Dzyaloshinskii-Moriya interaction (iDMI) extracted from Brillouin light scattering revealed that sample with W has a value of -0.52 mJ/m(2), which is similar to 2.5 times larger than Ta case. In addition to iDMI, the perpendicular magnetic anisotropy is also stronger for W case due to the orbital hybridization at the interface. From magnetic force microscopy, W sample showed a change from unusual rod-like domains to skyrmions, while the change was from labyrinth domains to skyrmions in Ta-based structure.