Investigation Of Perpendicular Exchange Bias For IrMn/[Pt/Co] And IrMn/[Pt/CoFe]

FM/AFM exchange bias film is an important issue of the GMR spin valve and the Magnetic tunnel junction. This dissertation systematically studied the influence of Pt thickness on the perpendicular exchange bias property for IrMn/Co60Fe40/[Pt/Co90Fe10] and IrMn/Co60Fe40/[Pt/Co].The IrMn/Co60Fe40/[Pt/Co90Fe10] and IrMn/Co60Fe40/[Co/Pt] multilayer samples, in which the thickness of the Pt layers were different, were deposited on thermal oxidation of single crystalline silicon substrate by using DC magnetron sputtering at room temperature. Each magnetic layer (Co, Co90Fe10 and Co60Fe40) was selected as 6A and the second Pt layer above IrMn layer was adopt a relatively large thickness (15A or 20A) which maintained the perpendicular magnetization. The results show that the scope of the single state of magnetization approximately reaches 400 Oe with Pt layer (t1, t2) of 6 A, which greatly exceed various room temperature perpendicular exchange bias systems ever reported. The Co90Fe10 system, compared to the Co system, has lower coercivity and smaller bias field. So the two systems exhibit equal perpendicular exchange bias performance. The perpendicular exchange bias performance of IrMn/Co60Fe40/[Pt/Co90Fe10] with Pt thickness resembles that of IrMn/Co60Fe40/[Pt/Co].On the basis of Co60Fe40 inserted layer, Firstly, the Co90Fe10/Pt was used as the biased ferromagnetic layer. Secondly, every Pt layer was selected different thickness. The present work improved the scope of a single state of magnetization, all samples showed well-defined perpendicular magnetic anisotropy with fairly square perpendicular loop.