Seed Layer And The Thickness Of Antiferromagnetic Exchange Bias Formation And Thermal Stability Of Nife / Ptmn Bilayers

Exchange coupling between an antiferromagnet(AF) and a ferromagnet(FM) across their common interface, due to its intriguing physics and the key role in giant magnetoresistance effect spintronic devices, has become an international hotspot. In this dissertation, the magnetism property on the exchange bias of (Ni_0.81Fe_0.19)_1-XCr_X /NiFe/PtMn films were systematically investigated.In the (Ni_0.81Fe_0.19)_1-XCr_X /NiFe/PtMn films, the grain size of PtMn layer depended strongly on the variety of Cr concent. The exchange bias of NiFe/PtMn bilayers change differently with the variety of Cr concentration and the thickness of PtMn. The experiments show that the exchange bias field depends strongly on the grain size of PtMn layer. When the size of grain is around 11.3nm, the exchange field attained their maximum. Thermal stability of exchange bias indicates that (Ni_0.81Fe_0.19)_1-XCr_X /NiFe/PtMn films with bigger PtMn grains have a higher blocking temperature, and the bigger grain size is good for decreasing the critical thickness of PtMn layer, which is consistent with Mauri's model.