Magnetoresistive Element Functional Layer Crystalline Orientation
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Solution Overview
Problem
Conventional magnetoresistive elements with spin filter layers have insufficient differences in up-spin and down-spin electron permeation, limiting their magnetoresistive ratio and sensitivity in high-density magnetic recording applications.
Innovation Solution
Incorporating a functional layer made of oxygen- or nitrogen-containing materials with a crystalline orientation plane different from its adjacent layers, arranged between the pinned and free layers, to enhance the spin filter effect and increase the magnetoresistive ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional spin filter layer is used in the magnetoresistive element, then the device structure is simple and manufacturing is easier, but the difference between up-spin and down-spin electron permeation is insufficient, resulting in low magnetoresistive ratio
Solution Approach 1:
The patent employs composite material structures including oxide layers (e.g., MgO, Al2O3), nitride layers (e.g., TiN, TaN), and oxynitride layers in combination with ferromagnetic layers. These composite structures create enhanced spin filtering effects through interface engineering and crystalline orientation control, achieving superior magnetoresistive ratios compared to conventional single-material spin filter layers.
Solution Approach 2:
The patent introduces functional layers with specific local properties at critical interfaces within the magnetoresistive structure. By controlling the crystalline orientation (e.g., (001) orientation for MgO), thickness, and composition of oxide/nitride/oxynitride layers at specific locations, the spin filtering capability is locally enhanced without redesigning the entire device structure.
2Measurement precision
If the magnetoresistive ratio is increased by improving spin filter performance, then the sensitivity to magnetic field detection is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent optimizes critical parameters including layer thickness (e.g., oxide layer thickness of 1-3 nm), crystalline orientation (e.g., (001) orientation), and composition ratios in the oxide/nitride/oxynitride layers. By precisely controlling these parameters during deposition, the spin filtering performance and magnetoresistive ratio are enhanced while maintaining compatibility with existing manufacturing processes.
Solution Approach 2:
The patent incorporates seed layers and buffer layers with specific crystalline orientations before depositing the functional oxide/nitride/oxynitride layers. This preliminary action ensures that subsequent layers develop the desired crystalline orientation and interface quality, simplifying the overall manufacturing process by preventing defects rather than correcting them later.
3Length of moving object
If a thin spin filter layer is used to achieve narrower head gap, then the device size is reduced, but the difference between up-spin and down-spin electron permeation becomes insufficient
Solution Approach 1:
The patent uses composite oxide/nitride/oxynitride layer structures that provide enhanced spin filtering per unit thickness compared to conventional materials. The interface effects and crystalline orientation control in these composite layers compensate for the reduced thickness, maintaining sufficient electron permeation difference while enabling narrower head gaps for higher recording density.
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 solution significantly improves the magnetoresistive ratio and sensitivity, enabling more effective detection of magnetic fields in high-density recording systems by varying the crystalline orientation of the functional layer, leading to better discrimination between '0' and '1' signals.
Implementation Method 1
The performance of magnetic devices, particularly magnetic heads, has been drastically improved by using the giant magnetoresistive effect (GMR) and tunneling magnetoresistive effect (TMR).
Implementation Method 2
The performance of magnetic devices, particularly magnetic heads, has been drastically improved by using the giant magnetoresistive effect (GMR) and tunneling magnetoresistive effect (TMR).
Implementation Method 3
The thin film layer is permeable preferentially to either up-spin electrons or down-spin electrons, thus contributing to production of higher magnetoresistive ratio (MR ratio). Such thin film layer is called a spin filter layer (SF layer).
Data Source
AI summary
A magnetoresistive element includes a magnetoresistive film including a magnetization pinned layer, a magnetization free layer, an intermediate layer arranged between the magnetization pinned layer and the magnetization free layer, a cap layer arranged on the magnetization pinned layer or on the magnetization free layer, and a functional layer formed of an oxygen- or nitrogen-containing material and arranged in the magnetization pinned layer, or in the magnetization free layer, and a pair of electrodes which pass a current perpendicularly to a plane of the magnetoresistive film, in which a crystalline orientation plane of the functional layer is different from a crystalline orientation plane of its upper or lower adjacent layer.