Perpendicular exchange-biased [Co/Pt]3Co(tCo)IrMn and IrMn/Co(tco)/Pt/[Co/Pt]3multilayers have been fabricated, changing the thickness (tCo)of the cobalt that is next to the IrMn layer. The crystal structure, interface roughness and magnetic properties were characterized by X-ray diffraction (XRD), X-ray reflectivity (XRR), atomic force microscopy (AFM) and extraordinary Hall Effect (EHE). The multilayers are flat, and the roughness is about 0.2 nm across the 2-μm scanning range. The magnetization reversal is dependent on tCo, and the exchange bias and coercivity vary with tCo. The exchange bias reaches a maximum value (about 13.9 mT) for top-pinned multilayers at tCo=0.45 nm, while it reaches a maximum (about 3.5 mT) for bottom-pinned multilayers at t Co=0.6 nm. For both stacks the coercivity is maximum (about 30 mT) at tCo=0.8nm, and stable for tCo>1.0nm. These results are well understood in terms of the Co spin orientation at the Co/IrMn interface.
Bibliographical noteFunding Information:
This work was supported by Science Foundation Ireland as part of MANSE project, and by the Ireland-China Scientific Exchange Scheme. The authors are also grateful for the partial support of the State Key Project of Fundamental Research, Ministry of Science and Technology (MOST), under Grant 2006CB932200, Chinese National Natural Science Foundation (NSFC), under Grants 10574156, 50528101 and 50721001, and Ireland-China Joint Research Project between SFI and MOST.
- Magnetization reversal
- [Co/Pt] perpendicular multilayers