Multilayer Side Shield for Magnetic Read Head Noise Reduction
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Solution Overview
Problem
Current magnetic read head sensors face challenges in achieving further improvements in recording density due to limitations in sensor design and film characteristics, particularly in reducing noise and interference from adjacent tracks.
Innovation Solution
The introduction of side shields with a multilayer structure, including antiferromagnetic coupling, to enhance the magnetic permeability and stability of the read head sensor, allowing for improved domain control and reduced skirt sensitivity, thereby increasing track density and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If side shields are added to the read head sensor, then reading noise is reduced and resolution is improved, but device complexity increases
Solution Approach 1:
The side shield is divided into multiple magnetic layers (first magnetic layer, second magnetic layer, third magnetic layer) separated by nonmagnetic layers, allowing each layer to be independently optimized for specific functions such as noise reduction and domain control
Solution Approach 2:
The side shield employs a composite multilayer structure combining ferromagnetic materials (for magnetic shielding) with nonmagnetic materials (for separation and coupling control), creating a functionally optimized composite structure that reduces reading noise while maintaining domain stability
2Stability of the object's composition
If multilayer structure with antiferromagnetic coupling is used in side shield, then magnetic permeability and domain control are improved, but manufacturing complexity increases
Solution Approach 1:
The patent utilizes antiferromagnetic coupling between magnetic layers to fundamentally change the magnetic interaction parameters, creating stable domain configurations that maintain consistent magnetic properties under varying operating conditions
Solution Approach 2:
Nonmagnetic layers serve as intermediaries between magnetic layers, controlling the coupling strength and magnetic interaction while simplifying the manufacturing process by providing clear separation interfaces for deposition
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
The multilayer side shield structure enhances magnetic permeability, reduces reading noise, and improves resolution, enabling higher track per inch (TPI) and bit per inch (BPI) recording densities while maintaining domain stability.
Implementation Method 1
The bias direction of the read head sensor is antiparallel to the bottom layer of the upper shield
Implementation Method 2
The read head of a hard disk drive includes a spin valve element utilizing a magnetoresistive effect. By sensing the relative magnetizations of two ferromagnetic thin films sandwiching an intermediate layer, magnetic information can be read from nanoscale magnets on the disk
Implementation Method 3
The upper magnetic layer is ferromagnetically coupled to a bottom layer of the upper shield
Data Source
AI summary
The embodiments disclosed generally relate to a read head sensor in a magnetic recording head. The read head sensor comprises side shields in addition to the upper and lower shields. The upper shield sensor is a multilayer structure with antiferromagnetic coupling. The side shield is a multilayer structure whereby a lower magnetic layer is separated from an upper magnetic layer. The upper magnetic layer is ferromagnetically coupled to a bottom layer of the upper shield. The bias direction of the read head sensor is antiparallel to the bottom layer of the upper shield.