Hgst Netherlands, B.v.

Shi-Ling Chang Wang

Bruce Alvin Gurney

Ricardo Ruiz

Qing Zhu

Manfred Ernst Schabes

Kentaro Takano

Han Zou

Dan Saylor Kercher

Alan C Lam

A perpendicular magnetic recording disk includes a template layer below a Ru or Ru alloy underlayer, with a granular Co alloy recording layer formed on the underlayer. substrate. The template layer comprises nanoparticles spaced-apart and partially embedded within a polymer material, with the nanoparticles protruding above the surface of the polymer material. A seed layer covers the surface of the polymer material and the protruding nanoparticles and an underlayer of Ru or a Ru alloy covers the seed layer. The protruding nanoparticles serve as the controlled nucleation sites for the Ru or Ru alloy atoms. The nanoparticle-to-nanoparticle distances can be controlled during the formation of the template layer. This enables control of the Co alloy grain diameter distribution as well as grain-to-grain distance distribution.

Perpendicular magnetic recording disk with template layer formed of nanoparticles embedded in a polymer material

A continuous-media perpendicular magnetic recording disk has a granular recording layer (RL) with controlled grain pitch distribution and controlled long range ordering of the grains. The disk includes a substrate with a template layer for the RL that comprises a blend of at least two different sized nanoparticles. The nanoparticles have a nanoparticle core with attached polymer ligands. The nanoparticle cores protrude above the surface of the template layer to provide a nonplanar surface topology. The blend of two sizes of nanoparticles causes the RL to have low grain pitch distribution and a disruption of long range ordering so that there are no large magnetic rafts. One of the nanoparticles types has a diameter greater than 105% of the diameter of the other nanoparticle type and is present in the total blend of nanoparticles of between about 5% and 35% or between about 55% and 90%.

Perpendicular magnetic recording disk with template layer formed of a blend of nanoparticles

A method for making a perpendicular magnetic recording disk includes forming a template layer below a Ru or Ru alloy underlayer, with a granular Co alloy recording layer formed on the underlayer. The template layer is formed by depositing a solution of a polymer with a functional end group and nanoparticles, allowing the solution to dry, annealing the polymer layer to thereby form a polymer layer with embedded spaced-apart nanoparticles, and then etching the polymer layer to a depth sufficient to partially expose the nanoparticles so they protrude above the surface of the polymer layer. The protruding nanoparticles serve as controlled nucleation sites for the Ru or Ru alloy atoms. The nanoparticle-to-nanoparticle distances can be controlled during the formation of the template layer. This enables control of the Co alloy grain diameter distribution as well as grain-to-grain distance distribution.

Method for making a perpendicular magnetic recording disk with template layer formed of nanoparticles embedded in a polymer material

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San Ramon, CA, United States of America

Shi-Ling Chang Wang