CPP Magnetoresistive Element with Orthogonal Shield Layers
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Solution Overview
Problem
Conventional magnetoresistive effect elements face challenges in achieving ultra-high recording density due to limitations in narrowing the read gap between shield layers, which affects heat dissipation and reliability, and are prone to erroneous writing and demagnetization due to leakage magnetic fields.
Innovation Solution
A CPP structure magnetoresistive effect element with inclined magnetization shield layers and exchange coupling gap layers, eliminating the need for antiferromagnetic layers and bias magnetic fields, allowing for orthogonal magnetization states without external bias, thereby narrowing the read gap and preventing signal degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the read gap between upper and lower shield layers is narrowed to achieve ultra-high recording density, then linear recording density is improved, but heat dissipation efficiency decreases and reliability deteriorates
Solution Approach 1:
The invention changes the magnetization orientation from in-plane to perpendicular-to-plane (CPP) structure, utilizing the vertical dimension for current flow. This dimensional change enables narrower read gap for higher recording density while maintaining adequate heat dissipation through the vertical current path, resolving the contradiction between recording density and heat dissipation efficiency
Solution Approach 2:
The invention changes the magnetization direction parameter from parallel to perpendicular relative to the film plane. This parameter change in the CPP structure allows the read gap to be narrowed without compromising heat dissipation, as the perpendicular current flow path provides efficient thermal management while enabling ultra-high recording density
2Reliability
If conventional spin-valve GMR element structure with antiferromagnetic layers is used, then magnetization pinning is achieved, but leakage magnetic fields cause erroneous writing and demagnetization
Solution Approach 1:
The invention extracts and removes the antiferromagnetic layer from the conventional spin-valve structure. By eliminating this layer, the source of leakage magnetic fields that causes erroneous writing and demagnetization is removed, while the desired magnetization pinning functionality is maintained through alternative design approaches in the CPP structure
Solution Approach 2:
The invention converts the potential harm of complex multilayer structures that generate leakage fields into a benefit by using a simplified CPP structure. The perpendicular magnetization configuration inherently confines magnetic fields more effectively, transforming the structural complexity issue into an advantage for reducing erroneous writing and demagnetization
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 configuration enhances recording density, improves heat dissipation, and prevents erroneous writing and demagnetization by maintaining orthogonal magnetization states without external bias, ensuring reliable signal detection and reduced leakage magnetic fields.
Implementation Method 1
a magnetoresistive effect part; and an upper shield layer and a lower shield layer that are laminated and formed in a manner sandwiching the magnetoresistive effect part from above and below
Implementation Method 2
the first ferromagnetic layer is indirectly magnetically coupled with the upper shield layer via a first exchange coupling function gap layer that is positioned between the first ferromagnetic layer and the upper shield layer
Data Source
AI summary
A magnetoresistive effect element that prevents a recording medium from deteriorating by effectively inhibiting erroneous writing to a medium or the like includes a magnetoresistive effect part, and an upper shield layer and a lower shield layer that are laminated and formed in a manner sandwiching the magnetoresistive effect part from above and below, and is in a current perpendicular to plane (CPP) structure in which a sense current is applied in a lamination direction. The magnetoresistive effect part includes a nonmagnetic intermediate layer, and a first ferromagnetic layer and a second ferromagnetic layer that sandwich the nonmagnetic intermediate layer from above and below, the upper shield layer and the lower shield layer have inclined magnetization structures in which magnetizations of them are respectively inclined with respect to a track width direction, the magnetizations of the upper shield layer and the lower shield layer are mutually substantially orthogonal, the first ferromagnetic layer is indirectly magnetically coupled with the upper shield layer via a first exchange coupling function gap layer that is positioned between the first ferromagnetic layer and the upper shield layer, and the second ferromagnetic layer is indirectly magnetically coupled with the lower shield layer via a second exchange coupling function gap layer that is positioned between the second ferromagnetic layer and the lower shield layer.