Perpendicular Magnetic Recording Medium Seed Layer Design

Solution Overview

Problem

Conventional perpendicular magnetic recording media face limitations in simultaneously reducing magnetic grain size and achieving high orientation of the recording layer, which restricts further noise reduction and increased surface recording density.

Innovation Solution

A perpendicular magnetic recording medium structure is introduced, featuring a nonmagnetic seed layer with a first amorphous layer and a second layer with a face-centered cubic (fcc) structure, using refractory materials like Ta, W, Nb, Mo, or Zr, to reduce crystal grain size and enhance orientation, thereby reducing medium noise and increasing recording density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a single-layer seed structure is used, then the structure is simple, but it cannot simultaneously reduce magnetic grain size and achieve high orientation

Engineering Contradiction:

Improvemagnetic grain size and orientationVSAvoidseed layer structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The seed layer is divided into two distinct layers: a first seed layer (amorphous material) and a second seed layer (fcc structure). This segmentation allows each layer to perform its specific function - the first layer reduces magnetic grain size while the second layer achieves high orientation, resolving the contradiction between manufacturing precision and structural simplicity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses composite material structure combining amorphous material (Ta, W, Nb, Mo, or Zr) in the first seed layer and fcc structure material in the second seed layer. This composite approach enables simultaneous achievement of magnetic grain size reduction and high orientation that cannot be obtained with a single material system.

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If magnetic grain size is reduced to decrease medium noise, then medium noise is reduced, but it becomes difficult to simultaneously achieve high orientation

Engineering Contradiction:

Improvemedium noiseVSAvoidcrystal orientation

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The seed layer is divided into two distinct layers: a first seed layer (amorphous material) and a second seed layer (fcc structure). This segmentation allows each layer to perform its specific function - the first layer reduces magnetic grain size while the second layer achieves high orientation, resolving the contradiction between manufacturing precision and structural simplicity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses composite material structure combining amorphous material (Ta, W, Nb, Mo, or Zr) in the first seed layer and fcc structure material in the second seed layer. This composite approach enables simultaneous achievement of magnetic grain size reduction and high orientation that cannot be obtained with a single material system.

Inventive Principle:

Principle #40Composite materials

3Quantity of substance

If surface recording density is increased, then storage capacity increases, but medium noise increases

Engineering Contradiction:

Improvesurface recording densityVSAvoidmedium noise

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The invention uses a dual-layer seed structure that creates optimal magnetic grain characteristics (smaller size and uniform distribution) in the perpendicular recording layer, thereby reducing medium noise while enabling higher surface recording density.

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The invention uses composite material structure combining amorphous material (Ta, W, Nb, Mo, or Zr) in the first seed layer and fcc structure material in the second seed layer. This composite approach enables simultaneous achievement of magnetic grain size reduction and high orientation that cannot be obtained with a single material system.

Inventive Principle:

Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This structure allows for simultaneous reduction of magnetic grain size and achievement of high orientation, leading to lower medium noise and increased surface recording density in magnetic storage apparatuses.

Implementation Method 1

the perpendicular recording layer that is epitaxially grown on the nonmagnetic intermediate layer

Methodology Applied

Scientific EffectEpitaxy: Epitaxy

Data Source

PatentUS7871718B2Perpendicular magnetic recording medium and magnetic storage apparatus

Publication Date: 2011.01.18 RESONAC HARD DISK CORP

AI summary

A perpendicular magnetic recording medium includes a nonmagnetic seed layer, a nonmagnetic intermediate layer provided on the nonmagnetic seed layer, and a perpendicular recording layer provided on the nonmagnetic intermediate layer. The nonmagnetic seed layer includes a first seed layer made of an amorphous material, and a second seed layer provided between the first seed layer and the nonmagnetic intermediate layer and made of a material having a fcc structure. The amorphous material includes at least one element selected from a group consisting of Ta, W, Nb, Mo, Zr and alloys thereof which include at least one of Ta, W, Nb, Mo and Zr as a main component exceeding 50 at. %.