Spin Accumulation Magnetic Sensor Gap Reduction
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Solution Overview
Problem
Current magnetoresistive sensors, such as GMR and TMR sensors, face limitations in reducing gap thickness while maintaining strong signal quality and low noise, which hinders the increase in data density in magnetic data storage devices.
Innovation Solution
A spin accumulation sensor design featuring first and second magnetic free layers that are magnetically anti-parallel coupled, along with a spin injection structure and a non-magnetic conductive layer, enhances sensor performance by reducing gap thickness and minimizing signal noise through improved spin current management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If traditional magnetoresistive sensors (GMR or TMR) are used, then the sensor can detect magnetic signals, but the gap thickness cannot be significantly reduced while maintaining strong signal quality
Solution Approach 1:
The sensor is divided into two separate functional structures: a spin injection structure located away from the air bearing surface and a detector structure located near the air bearing surface. These structures are connected by a non-magnetic conductive layer that extends between them. This segmentation allows the gap thickness to be reduced independently while maintaining signal quality through the distributed architecture.
Solution Approach 2:
The sensor design transitions from a single-plane stacked layer structure to a three-dimensional configuration where the spin injection structure and detector structure are separated in space and connected via a conductive pathway. This dimensional change enables reduced gap thickness while preserving magnetic signal detection capability through the extended conductive connection.
2Productivity
If the spacing between magnetic shields is reduced to increase data density, then bit length decreases, but signal noise increases and signal strength decreases
Solution Approach 1:
A non-magnetic, electrically conductive layer serves as an intermediary between the spin injection structure and the detector structure. This conductive layer facilitates spin current transport while being magnetically transparent, allowing the detector to sense magnetic fields from the media without interference from the conductive connection itself. This intermediary enables reduced shield spacing while maintaining signal-to-noise ratio.
3Power
If a second magnetic free layer is added to the detector structure, then sensor output voltage increases, but device complexity increases
Solution Approach 1:
The detector structure combines multiple magnetic free layers (first and second magnetic free layers) that are magnetically anti-parallel coupled with each other. This merging of multiple layers within a single detector structure enables enhanced output voltage through constructive interference of spin signals while maintaining a unified structural design that manages complexity.
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 sensor achieves increased output voltage and reduced magnetic noise by utilizing a second magnetic free layer and a second magnetic layer in the spin injection structure, leading to enhanced data storage density and efficiency.
Implementation Method 1
spin accumulation sensor
Implementation Method 2
spin injection structure
Implementation Method 3
Giant Magnetoresistive (GMR) sensor
Implementation Method 4
Tunnel Junction Magnetoresisive (TMR) sensor
Implementation Method 5
magnetically anti-parallel coupled
Data Source
AI summary
A spin accumulation magnetic sensor having improved signal strength and efficiency. The spin accumulation magnetic sensor has a detector structure and a spin injection structure and has a non-magnetic, electrically conductive layer extending between the spin injection structure and the detector structure. The detector structure has first and second free layers arranged such that the non-magnetic, electrically conductive layer extends between them and so that they are magnetically anti-parallel coupled with one another. The spin injection structure can also include first and second magnetic layers with the electrically conductive layer extending between them and with the first magnetic layer being pinned and the second magnetic layer being anti-parallel coupled with the first magnetic layer.