The perpendicular magnetic properties of glass/Ta/Cu/[Co/Ni]4/Ta multilayers can be efficiently tuned by in situ pre-annealing the Ta/Cu under-layers at various temperatures (TCu) before the deposition of the Co/Ni stack. As a result of the co-effect of fcc(111) texture and Cu surface roughness, the perpendicular anisotropy Ku and coercivity H c⊥ exhibit a similar non-monotonous dependence on the T Cu, showing minimum values at TCu = 100 °C and maxima at 400 °C for Ku while at 550 °C for Hc⊥. By in situ annealing the under-layers at 550 °C and then post-annealing the whole stack at 250 °C, the Hc⊥ value can be significantly enhanced from 139 Oe up to 620 Oe, which is important for spintronic applications.
Bibliographical noteFunding Information:
This work was supported by the National Basic Research Program of China (2014CB921104) and the National Natural Science Foundation of China (Grant Nos. 51222103, 11274113, 11074046, 51171047, and 61078030). Z. Zhang thanks for the support from the Program for New Century Excellent Talents in University (NCET-12-0132). B. Ma thanks the NSFC (Nos. 51071046 and 11174056) for their support.