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▲ [15a-C41-5] Observation of perpendicular exchange bias in Ir-doped Fe2O3/Co thin film system
キーワード:Cr2O3, Fe2O3
The exchange coupling phenomenon at the interface between a ferromagnet (FM) and an antiferromagnet (AFM) has possible applications in spintronic devices. α-Fe2O3 (Hematite) is the most stable iron oxide, and it has high Neel temperature (TN) of 955 K. Thus α-Fe2O3/FM system is expected to work at high temperature with high stability. Till now, perpendicular was not observed forα-Fe2O3 /FM thin film system; only Hex for in-plane direction was reported [1]. Because the spin direction ofα-Fe2O3 lies parallel to ab-plane above Morin temperature TM ~ 263 K, it was difficult to observe perpendicular Hex. On the other hand, in the present spintronic devices, spin direction perpendicular to the film plane is necessary. Our group successfully enhanced TM of α-Fe2O3 thin film to around 400 K by Ir doping [2]. In this work, we fabricated the Ir-doped α-Fe2O3 (Ir-Fe2O3)/Co exchange coupled thin film and investigated its dependence on Ir-Fe2O3 thickness. The sample structures are c-Al2O3 substrate/Ir-Fe2O3 x/Co 1/Pt 5 (nm). The perpendicular Hex was observed in this thin film system even for 1-nm-thick Ir-Fe2O3 film. Fig. 1 shows temperature dependence of perpendicular Hex and Hc of c-Al2O3 substrate/Ir-Fe2O3 5/Co 1/Pt 5 (nm). Details of thickness dependence will be reported.
This work was partly funded by ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Japan Government).
[1] J. Dho et al., Phys. Rev. B, 71 (2005) 180402.
[2] N. Shimomura et al., J. Appl. Phys., 117 (2015) 17C736.
This work was partly funded by ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Japan Government).
[1] J. Dho et al., Phys. Rev. B, 71 (2005) 180402.
[2] N. Shimomura et al., J. Appl. Phys., 117 (2015) 17C736.