Magnetoresistive Element Functional Layer Nitrogen Iron Composition
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Solution Overview
Problem
Conventional magnetoresistive elements with spin filter layers are insufficient in distinguishing between up-spin and down-spin electron permeation, limiting the magnetoresistive ratio (MR ratio) and thus the recording density in magnetic recording devices.
Innovation Solution
A magnetoresistive element with a functional layer comprising nitrogen and a metal material containing 5 atomic % or more of Fe, arranged between the magnetization pinned and free layers, and subjected to repeated deposition and nitriding treatment to enhance the spin filter effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional spin filter layer is used, then the device structure is simple, but the magnetoresistive ratio is insufficient
Solution Approach 1:
The patent applies composite materials by creating a spin filter layer with a specific composite structure: a metal layer containing Fe, Co, and Ni (with Fe at 5-50 at%, Co at 30-60 at%, Ni at 5-30 at%) combined with an oxide layer. This composite structure enhances the magnetoresistive ratio by improving spin-dependent electron permeation while maintaining a manageable layer configuration.
Solution Approach 2:
The patent employs parameter changes by optimizing the compositional parameters of the spin filter layer. Specifically, it defines precise atomic percentage ranges for Fe (5-50 at%), Co (30-60 at%), and Ni (5-30 at%), along with controlling the thickness of the metal layer (0.5-5 nm) and oxide layer (0.5-5 nm). These parameter optimizations enhance the magnetoresistive effect while managing structural complexity.
2Reliability
If the spin filter effect is enhanced, then the magnetoresistive ratio improves, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies preliminary action by forming the metal layer with specific compositional characteristics (Fe, Co, Ni ratios) before the oxide layer is deposited. This preliminary structuring of the metal layer with controlled thickness (0.5-5 nm) and composition enables subsequent oxide layer formation to proceed more efficiently, enhancing the spin filter effect while managing manufacturing complexity through staged deposition.
Solution Approach 2:
The patent segments the spin filter layer into two distinct functional layers: a metal layer (containing Fe, Co, Ni in specific ratios) and an oxide layer. This segmentation allows each layer to be optimized independently for its specific function—the metal layer for spin-dependent electron transport and the oxide layer for tunneling barrier properties—thereby enhancing the magnetoresistive ratio while organizing the manufacturing process into manageable stages.
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 enhanced spin filter layer improves the magnetoresistive ratio, enabling higher recording density without increasing the device's volume, thus addressing the limitations of conventional spin filter layers.
Implementation Method 1
a functional layer arranged in the magnetization pinned layer, in the magnetization free layer, in the interface between the magnetization pinned layer and the intermediate layer, in the interface between the intermediate layer and the magnetization free layer, or in the interface between the magnetization pinned layer or the magnetization free layer and the cap layer; the functional layer being formed of a layer comprising nitrogen and a metal material containing 5 atomic % or more of Fe
Implementation Method 2
In the spin-valve film, the magnetization of one ferromagnetic layer (referred to as a "pinned layer" or "magnetization pinned layer") is pinned by an antiferromagnetic layer or the like, whereas the magnetization of the other ferromagnetic layer (referred to as a "free layer" or "magnetization free layer") is made rotatable in accordance with an external magnetic field. In the spin-valve film, a giant magnetoresistace change can be produced by a change of the relative angle between the magnetization directions of the pinned layer and the free 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 arranged in the magnetization pinned layer, in the magnetization free layer, in the interface between the magnetization pinned layer and the intermediate layer, in the interface between the intermediate layer and the magnetization free layer, or in the interface between the magnetization pinned layer or the magnetization free layer and the cap layer, and a pair of electrodes which pass a current perpendicularly to a plane of the magnetoresistive film, in which the functional layer is formed of a layer including nitrogen and a metal material containing 5 atomic % or more of Fe.