Perpendicular Magnetization MR Element for Noise Reduction
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Solution Overview
Problem
Conventional magnetoresistive (MR) elements with a spin-valve effect face increased unstable magnetization regions as they are miniaturized, leading to higher noise and reduced output due to the parallel magnetization direction of the free layer to the film surface, necessitating bias layers for magnetic domain control.
Innovation Solution
The MR element is designed with a pinned layer and a free layer where the magnetization direction of the free layer is perpendicular to the film surface, eliminating unstable magnetization regions and eliminating the need for bias layers, allowing for simplified configuration and miniaturization while maintaining high output through a spin-valve structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the magnetization direction of the free layer is parallel to the film surface, then the MR element can be miniaturized, but the ratio of unstable magnetization regions to entire element area increases greatly
Solution Approach 1:
The patent inverts the conventional magnetization direction configuration by making the free layer's magnetization direction perpendicular to the film surface instead of parallel, while keeping the pinned layer's magnetization parallel to the surface. This inversion eliminates unstable magnetization regions at the edges of the free layer, allowing miniaturization without sacrificing reliability.
2Device complexity
If the magnetization direction of the free layer is parallel to the film surface, then the MR element structure is conventional, but bias layers are necessary to control magnetic domains
Solution Approach 1:
The patent extracts and removes the bias layers from the MR element structure by adopting perpendicular magnetization in the free layer. This configuration inherently stabilizes the magnetization without requiring external bias layers for magnetic domain control, thereby simplifying the device structure while maintaining reliability.
3Object-generated harmful factors
If the free layer has parallel magnetization to the film surface, then the configuration is conventional, but unstable magnetization regions produce higher noise and reduced output
Solution Approach 1:
The patent inverts the magnetization configuration from parallel to perpendicular orientation in the free layer, which eliminates the edge effects that cause unstable magnetization regions. This inversion directly reduces noise and improves output signal quality without adding structural 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
This configuration reduces the area of unstable magnetization regions, resulting in higher output and lower noise, facilitating easier fabrication and miniaturization of the MR element, and maintaining high output comparable to conventional MR elements.
Implementation Method 1
An MR element includes a pinned layer, a free layer and a nonmagnetic space layer or a tunnel barrier layer sandwiched between the pinned layer and the free layer
Implementation Method 2
The present invention relates to a magnetoresistive effect (MR) element utilizing a spin-valve effect
Data Source
AI summary
An MR element includes a pinned layer, a free layer and a nonmagnetic space layer or a tunnel barrier layer sandwiched between the pinned layer and the free layer. A magnetization direction of the free layer is substantially perpendicular to a film surface thereof, and a magnetization direction of the pinned layer is substantially parallel to a film surface thereof.