Fabrication of $\hbox{L}1_{2}\hbox{–}\hbox{CrPt}_{3}$ Alloy Films Using Rapid Thermal Annealing for Planar Bit Patterned Media

Takeshi Kato,Daiki Oshima,Satoshi Iwata,Shigeru Tsunashima,Yukihiro Yamauchi

doi:10.1109/tmag.2010.2044559

Abstract

SiO 2 (2 nm)/Cr 25 Pt 75 (15 nm) and SiO 2 (2 nm)/Cr 25 Pt 75 (15 nm)/SiO 2 (10, 20 nm)/Co 80 Zr 10 Nb 10 (10 nm) were prepared by magnetron sputtering method and post-annealed by rapid thermal annealing (RTA) at temperatures of 600°C-1000°C for 1-60 sec. The saturation magnetization M s and coercivity H c measured by applying a maximum field of 18 kOe were 150 emu/cc and 12 kOe, respectively, for the sample after rapid thermal annealing at 1000 °C for 30 sec. This means that L1 2 -CrPt 3 phase was obtained by RTA process. The RTA process was applied to fabricate the multilayered structure having L1 2 -CrPt 3 and CoZrNb soft magnetic underlayer (SUL). The polar Kerr loop of CrPt 3 (15 nm)/SiO 2 (20 nm)/CoZrNb(10 nm) after RTA at 1000°C for 30 sec exhibited a large coercivity H c > 9 kOe corresponding to that of the CrPt 3 single layer. From the compositional depth profile of CrPt 3 (15 nm)/SiO 2 (20 nm)/CoZrNb(10 nm) processed by RTA at 1000°C for 30 sec, sharp layered structure was confirmed despite the high-temperature heat treatment. When the SiO 2 thickness was reduced to 10 nm, such a layered structure was completely destroyed due to the interdiffusion between CrPt 3 and CoZrNb layers. Thus it was concluded that the RTA process and the interlayer of SiO 2 (20 nm) were effective to fabricate layered structure having L1 2 -CrPt 3 and SUL.

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