The Recording of Tiny Marks Less Than 100 nm on Magneto-optical Medium Sputtered from RE-TM Alloy Target

Abstract

Use of magneto-optical (MO) medium sputtered from an intermetallic compound alloy target has advantages for mass production but may not be suitable for high-density recording due to its poor perpendicular magnetic anisotropy. The relationship between Ms Hc, the product of saturation magnetization Ms and coercivity Hc, and film microstructure is discussed in this paper; we obtained an Ms Hc of 1.3 × 10⁶ erg/cm³ using microcolumnar structure even when the medium was sputtered from an alloy target. By adopting this film for the memory layer in a DWDD system, tiny marks less than 100 nm in size can be reliably written. As a result, high-density recording at 15 Gbit/inch² is achieved.