Magnetoresistance Element With 0.1-0.3 nm Coupling Layer
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Solution Overview
Problem
Existing magnetoresistance effect elements face challenges in achieving both high thermal stability and low writing current, particularly in fine regions, due to limitations in miniaturization and dominant magnetic coupling mechanisms, which hinder the increase of the performance index Δ/IC0.
Innovation Solution
A magnetoresistance effect element structure is developed with a specific configuration including a first reference layer, a tunnel barrier layer, a magnetic layer with perpendicular magnetization, a non-magnetic coupling layer, and additional magnetic layers, where the non-magnetic coupling layer has a thickness of 0.1 nm to 0.3 nm, and the element size is 60 nm or smaller, optimizing the performance index Δ/IC0.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If element size is reduced to increase integration, then device complexity is reduced and capacity increases, but thermal stability factor decreases
Solution Approach 1:
The patent changes the magnetic anisotropy parameter from in-plane to perpendicular magnetization, and optimizes the thickness parameter of the nonmagnetic coupling layer (0.1-0.3 nm) to maintain thermal stability in miniaturized elements with 60 nm or smaller size
Solution Approach 2:
The patent uses composite material structures including CoFeB magnetic layers combined with specific nonmagnetic coupling materials (Ru, Rh, Ir, Os, Re, or their alloys) to achieve both miniaturization and high thermal stability through optimized magnetic coupling and anisotropy
2Area of stationary object
If element size is reduced to increase integration, then cell area decreases, but writing current becomes difficult to control and performance index deteriorates
Solution Approach 1:
The patent optimizes the thickness parameter of the nonmagnetic coupling layer (0.1-0.3 nm) to control magnetic coupling strength, enabling low writing current operation while maintaining high thermal stability in miniaturized elements, achieving superior performance index Δ/IC0
Solution Approach 2:
The patent applies different material compositions and thicknesses to specific layers (CoFeB layers with specific nonmagnetic coupling layers between them) to create localized magnetic properties that enable efficient spin transfer torque with reduced writing current
3Reliability
If interface area is increased to improve thermal stability, then thermal stability factor increases, but element size increases
Solution Approach 1:
The patent transitions from in-plane magnetization to perpendicular magnetization, effectively utilizing the vertical dimension for magnetic anisotropy, which allows enhanced thermal stability without increasing lateral element size through optimized interface magnetic anisotropy
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 enables a magnetoresistance effect element with improved thermal stability and reduced writing current, enhancing the performance index Δ/IC0, particularly in smaller sizes, by optimizing the magnetic coupling and anisotropy energy density.
Implementation Method 1
Writing bit information is performed by spin-transfer torque (STT) which uses a transfer of angular momentum intrinsic to electrons by directly passing a current through the magnetoresistance effect element
Implementation Method 2
TMR (Tunnel Magnetoresistance) through the tunnel barrier layer is used to read information
Implementation Method 3
a magnetic layer with perpendicular magnetization, optimizing the performance index Δ/IC0
Data Source
AI summary
A magnetoresistance effect element with a small element size can be provided which achieves both an increase in a thermal stability factor Δ and a reduction in a writing current IC0 and which improves a performance index Δ/IC0(μA−1) obtained by dividing the thermal stability factor Δ by the writing current IC0. The magnetoresistance effect element includes a first reference layer (B1), a first junction layer (11), a first magnetic layer (21), a first non-magnetic coupling layer (31), a second magnetic layer (22), and a second junction layer (12), and a film thickness of the first non-magnetic coupling layer (31) is 0.1 nm or more and 0.3 nm or less.