Exchange bias variations of the seed and top NiFe layers in NiFe/FeMn/NiFe trilayer as a function of seed layer thickness

Effect of Ta buffer and NiFe seed layers on pulsed-DC magnetron sputtered Ir20Mn80/Co90Fe10 exchange bias

“…These changes may be an indication to an interaction between these layers. In comparison to that, no adverse effect between H ex of bottom NiFe/FeMn and that of top FeMn/NiFe interface was found in the RF-MS deposited NiFe/FeMn/NiFe system [21]. Moreover, a slight increase in H ex of top FeMn/NiFe layer during the 1/t F fall of H ex of bottom NiFe seed layer was reported.…”

“…Consequently, the choice of ULs for the deposition of AF layer becomes crucial. Accordingly, different materials for AF layer as PtMn [3,8], FeMn [7,10,20,21], IrMn [4][5][6]9,[11][12][13][14][15][16][17][18][19]22,24,25] and different ULs [3][4][5][6][7][8][11][12][13][14][15][16][17][18]21,22] deposited using DC and RF magnetron sputtering (DC-MS, RF-MS) and ion beam sputtering [20] were established. In top EB systems, ULs as Ta/NiFe [6], Ta, Cu or Si [7,13,17,20], Cu, Ru or Cu/ Ru [4,5,15] provides the /1 1 1S texture in AF layer, in bottom type EB systems it was induced by Ta/AuCu [3]<...>…”

Bottom and top AF/FM interfaces of NiFe/FeMn/NiFe trilayers

“…For FeMn-based spin valve systems, the NiFe buffer layer is usually used to stabilize the AF g-phase, resulting in NiFe/FeMn/NiFe trilayer-like structure, where the bottom and top NiFe layers are, respectively, called as seed and pinned layers. When the seed and pinned layer thicknesses are different and/or the lower (NiFe/FeMn) and upper (FeMn/ NiFe) interfaces have substantial structural or/and magnetic differences, the spin valve has an asymmetrical M(H) curve with two regions: one related to the lower (NiFe/FeMn) interface and the other associated with the upper (NiFe/FeMn) one, each one with its respective H ex value [15][16][17].…”

“…Sankaranarayanan et al [15,16] have carried out a systematic investigation of the dependence of the EB main parameters (H ex and H C ) on the seed and pinned NiFe and also on the AF g-phase layer thicknesses, separately. The authors have observed that the lower FM/AF interfaces have H ex values larger than that of upper interfaces, whereas an opposite behavior was observed for the H C values.…”

“…The authors have observed that the lower FM/AF interfaces have H ex values larger than that of upper interfaces, whereas an opposite behavior was observed for the H C values. This difference in the EB parameters was attributed to distinct AF/FM spin configurations at the respective interfaces; however, the effect of the structural roughness was not taken into account [15,16]. Nevertheless, it has been reported [18] that the EB main parameters depend on several factors, such as: interfacial spin configuration, interface roughness between the FM and AF materials, textures (structural and magnetic), crystalline grain size and AF layer thickness.…”