Dual Free Layer Read Head Shield Seed Decoupling
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Solution Overview
Problem
Dual free layer (DFL) tunnel magnetic resistive (TMR) read heads face challenges in achieving stable transverse bias for their free layers, which is crucial for operating in scissor mode and reducing magnetic noise.
Innovation Solution
A magnetic read head design incorporating a non-magnetic spacer layer between the first shield and the magnetic seed layer, allowing for controlled coupling between the shields and seed layer, enabling stable transverse bias and improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a non-magnetic spacer layer is introduced between the shield and magnetic seed layer to control coupling, then readout amplitude and down-track resolution are improved, but device structure and manufacturing complexity increase
Solution Approach 1:
A non-magnetic spacer layer is introduced as an intermediary element between the shield and magnetic seed layer. This spacer layer mediates the magnetic coupling interaction, allowing precise control of the coupling strength to optimize readout amplitude and down-track resolution while maintaining a relatively simple overall device structure.
Solution Approach 2:
The thickness of the non-magnetic spacer layer is varied as a key parameter to control the magnetic coupling between the shield and seed layer. By adjusting this dimensional parameter, the device achieves optimal performance in readout amplitude and resolution without requiring complex structural modifications.
2Object-generated harmful factors
If the spacer layer thickness is optimized to control coupling, then magnetic noise is reduced and readout amplitude increases, but manufacturing precision requirements increase
Solution Approach 1:
The non-magnetic spacer layer serves as a controllable intermediary that provides a straightforward mechanism for noise reduction. Its non-magnetic properties inherently suppress unwanted magnetic coupling and noise, while its thickness can be precisely controlled during manufacturing to optimize readout amplitude.
Solution Approach 2:
The device employs a composite structure combining magnetic and non-magnetic layers with distinct functional properties. The non-magnetic spacer layer complements the magnetic seed layer and shield, creating a composite system where material property differences enable both noise reduction and controlled coupling.
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 controlled coupling via the non-magnetic spacer layer enhances readout amplitudes, reduces magnetic noise, and improves down-track resolution and reader width, leading to more effective data storage operations.
Implementation Method 1
A material and a thickness of the non-magnetic spacer layer is selected to control the coupling between the first shield and the magnetic seed layer of the DFL structure
Implementation Method 2
Dual free layer (DFL) tunnel magnetic resistive (TMR) read heads
Data Source
AI summary
The present disclosure generally relates to magnetic read heads comprising a dual free layer (DFL) structure. The magnetic read head comprises a first shield, a second shield, and a DFL structure disposed between the first and second shields. The DFL structure comprises a magnetic seed layer, a first free layer, and a second free layer. A non-magnetic spacer layer is disposed between and in contact with the first shield and the magnetic seed layer of the DFL structure at a media facing surface. A material and a thickness of the non-magnetic spacer layer is selected to control the coupling between the first shield and the magnetic seed layer of the DFL structure.