Metal-oxide buffer layer for maintaining topological bumpy surface underlayer of columnar CoPt-SiO2 granular media deposited at high substrate temperature

Kim Kong Tham, Shintaro Hinata, Shin Saito, Migaku Takahashi

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Investigation of surface topography for underlayer with various metal-oxide buffer layer (BL) materials for magnetic recording media is reported. In the previous study, it was found out that the application of a high substrate temperature deposition process to a granular layer with a magnetic alloy and a non-magnetic oxide material, such as CoPtCr-SiO2, will induce lamellar and spherical grains due to the flattening of the underlayer bumpy surface by recrystallization. By depositing a CoCr-SiO2 BL onto the Ru underlayer at room temperature, CoCr grains grow epitaxially onto Ru grains and SiO2 segregates to Ru boundaries. Consequently, bumpy surface morphology of the underlayer is maintained even though heated to around 400°C before depositing the granular layer. Therefore, CoPt magnetic grains of a Co82.4Pt17.6- 27.7 vol. % SiO2 granular film deposited on the underlayer grow epitaxially on CoCr grains with columnar structure. As a result, high average Ku of around 6.7×106erg/cm3 can be obtained. Among the studied BL materials, CoCr-SiO2 shows the highest thermal resistance with root mean square surface roughness (Rq) of around 1.7nm after heating at around 400°C. To obtain columnar magnetic grains with critical thickness more than 13nm, underlayer with Rq more than 1.6nm is needed.

Original languageEnglish
Article number17A923
JournalJournal of Applied Physics
Volume117
Issue number17
DOIs
Publication statusPublished - 2015 May 7

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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