Title :
High Mr squareness and exchange decoupled perpendicular recording media
Author :
Yamanaka, Kenji ; Hamamoto, Terufumi ; Nakano, Yukitaka ; Miura, Michiyori
Author_Institution :
Hoya Corp., Tokyo, Japan
fDate :
7/1/2001 12:00:00 AM
Abstract :
CoCr15Pt13 perpendicular layers with CoCr-alloy/Ti dual underlayers were annealed and it was investigated how the dual underlayer structure influences the characteristics of the CoCrPt perpendicular layer. The Ti layer thickness has a remarkable influence on the Cr diffusion efficiency from the upper underlayer of the dual underlayer into the CoCrPt perpendicular layer. The Cr diffusion efficiency is improved by increasing the Ti layer thickness and the addition of Ta or Pt to the upper underlayer of the dual underlayer. As a result, the magnetic properties were greatly improved. For the CoCr15Pt13(40 nm)/CoCr30Pt8Ta2(20 nm)/Ti(25 nm) media postannealed at 500°C for 30 min., the coercivity and Mr squareness were 7100 Oe and 0.98 respectively. Also, the slope of the MH loop at coercivity was nearly 1/4π
Keywords :
annealing; chromium alloys; cobalt alloys; coercive force; diffusion; exchange interactions (electron); ferromagnetic materials; perpendicular magnetic recording; platinum alloys; 500 degC; CoCr-alloy/Ti dual underlayers; CoCr15Pt13; CoCr15Pt13 perpendicular layers; CoCr30Pt8Ta2; CoCrPt perpendicular layer; Cr diffusion efficiency; Ti; Ti layer thickness; annealing; coercivity; dual underlayer; dual underlayer structure; exchange decoupled perpendicular recording media; high Mr squareness; magnetic properties; Annealing; Chromium alloys; Coercive force; Magnetic analysis; Magnetic properties; Perpendicular magnetic recording; Production; Research and development; Saturation magnetization; Temperature;
Journal_Title :
Magnetics, IEEE Transactions on
