Magnetic Head Soft Magnetic Layer Orientation for Noise Reduction
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Solution Overview
Problem
Conventional tunneling magnetoresistive (TMR) sensors suffer from noise generation due to a small anisotropic field perpendicular to the air bearing surface, which reduces the signal-to-noise ratio (SNR) in magnetic recording heads.
Innovation Solution
A magnetic head design featuring a soft magnetic layer with a close-packed plane positioned either parallel or oblique to the air bearing surface, increasing the anisotropic field and bias field applied to the free layer, thereby suppressing noise and enhancing SNR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the close-packed plane of the soft magnetic layer is positioned perpendicular to the air bearing surface (conventional structure), then the device complexity is reduced, but the anisotropic field becomes small which generates noise and reduces signal-to-noise ratio
Solution Approach 1:
The patent changes the orientation parameter of the close-packed plane of the soft magnetic layer from perpendicular to parallel or oblique relative to the air bearing surface. This parameter change increases the anisotropic field and bias field applied to the free layer, thereby suppressing noise and improving signal-to-noise ratio without fundamentally changing the device structure
Solution Approach 2:
The patent employs a composite structure consisting of the soft magnetic layer with specific crystallographic orientation (parallel or oblique close-packed plane) combined with the magnetoresistive sensor. This composite approach leverages the magnetic properties of the oriented soft magnetic layer to enhance the overall sensor performance and signal-to-noise ratio
2Reliability
If the close-packed plane of the soft magnetic layer is positioned parallel or oblique to the air bearing surface, then the anisotropic field and bias field are increased reducing noise, but the manufacturing precision requirements are increased
Solution Approach 1:
The patent modifies the orientation parameter of the close-packed plane to parallel or oblique positions, which fundamentally changes the magnetic field distribution. This parameter change naturally enhances the anisotropic field and bias field, achieving noise suppression through physical principle rather than complex control mechanisms
Solution Approach 2:
The patent establishes the correct orientation of the close-packed plane during the manufacturing process itself, rather than attempting to adjust it during operation. This preliminary action ensures the desired magnetic field characteristics are built into the device structure from the beginning, simplifying subsequent operations
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 increased anisotropic and bias fields improve the magnetic head's performance by reducing noise and increasing the signal-to-noise ratio, leading to better reading and writing capabilities in magnetic data storage systems.
Implementation Method 1
The close packed plane 106 of the side shield 104 has a small anisotropic field, Hk, perpendicular to the air bearing surface (ABS) 108
Implementation Method 2
a soft magnetic layer adapted to control a magnetization direction of the free layer and a magnetic domain of the free layer
Implementation Method 3
tunneling magnetoresistive (TMR) sensors are provided with a free layer and a side shield positioned on at least one end of the free layer
Data Source
AI summary
In one embodiment, a magnetic head includes a magnetoresistive sensor having a free layer and a soft magnetic layer adapted to control a magnetization direction of the free layer and a magnetic domain of the free layer, wherein a close-packed plane of the soft magnetic layer is positioned parallel to an air bearing surface (ABS) of the magnetic head. In another embodiment, a method for forming a magnetic head includes forming a magnetoresistive sensor having a free layer above a substrate and forming a soft magnetic layer adapted to control a magnetization direction of the free layer and a magnetic domain of the free layer, wherein a close-packed plane of the soft magnetic layer is positioned parallel or oblique to an ABS of the magnetic head.