Preparation And Spin Orbit Torque Control Of Perpendicular Exchange Biased Thin Films

Information storage technology is an extremely important technology in today’s digital society,which is directly related to the storage,transmission,and processing of data,and is the foundation of data flow in the information society.Whether it’s personal computers,enterprise servers,or the Internet of Things,cloud computing,artificial intelligence,and other fields,powerful storage technologies are needed to support the storage and processing of data.Due to its unique physical properties,perpendicular exchange bias structures are widely used in spin valves,magnetic tunnel junctions,and magnetic random access memories,providing a powerful boost for the development of new storage technologies.In this study,a perpendicular exchange bias structure thin film based on antiferromagnetic IrMn material was prepared using magnetron sputtering technology.The performance changes of various perpendicular exchange bias structures under the influence of component thickness,insertion of Pt layers,and annealing temperature were studied through anomalous Hall effect.The spin orbit torque effect was used to achieve directional modulation of the perpendicular exchange bias field.The specific research contents are as follows:In the study,[Pt/Co Fe B]_n/IrMn and[Pt/Co]_n/IrMn(n=1,4)top pinned exchange bias structures were first prepared.Through the measurement of the exchange bias field,the optimal thickness of the IrMn layer in the perpendicular exchange bias structure was obtained.Combined with the in and out of plane hysteresis loop tests,it was found that the coexistence of in and out of plane exchange bias fields could be achieved in some perpendicular exchange bias structures.Subsequently,in the study,the exchange bias performance was regulated by inserting an ultra-thin Pt layer into the ferromagnetic/antiferromagnetic layer interface.Due to the insertion of the Pt layer,the Pt/Co interface increases,improving the perpendicular anisotropy to a certain extent;At the same time,due to the influence of Pt intercalation on the ferromagnetic/antiferromagnetic interface,the exchange bias field derived from the interface effect can vary with the thickness of the Pt layer;In addition,the insertion of ultra-thin Pt layers during heat treatment has a certain blocking effect on the mutual diffusion of elements at the interface between the ferromagnetic layer and the antiferromagnetic layer,which can improve the thermal stability of the perpendicular exchange bias structure.By studying the variation of the cycle number n,we found that the single cycle perpendicular exchange bias structure has a larger exchange bias field and greater coercivity compared to the multi cycle structure,and its temperature stability is also better.Based on the excellent perpendicular exchange bias obtained,and based on the[Pt/Co]/IrMn single cycle perpendicular exchange bias structure,using the spin orbital torque effect generated by the heavy metal Pt layer to achieve modulation of the positive and negative directions of the perpendicular exchange bias field,it is determined that the spin orbital torque can not only drive the reversal of the magnetic moment of the magnetic layer Co,but also change the perpendicular exchange bias field by regulating the magnetic moment of the ferromagnetic/antiferromagnetic interface,Furthermore,it is possible to achieve a zero field spin orbit torque driven flip without lateral field assistance.Finally,the asymmetric effects of[Pt/Co]/IrMn perpendicular exchange bias structures driven by spin orbital torque were discovered in the study,and their applications in spin logic devices and magnetic storage were expanded.The AND gate,OR gate,NAND gate,NOR gate,and NOT gate logic units were constructed,and the magnetic storage of two and three states was realized,promoting the application of perpendicular exchange bias structures based on antiferromagnetic materials in spin electronics.