RuFe Magnetic Coupling Layer for Non-Collinear Magnetization
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Solution Overview
Problem
Current magnetic coupling layers, such as those using PtMn and RuFe, have limitations including weak coupling strength, limited ability to sense strong external magnetic fields, and instability upon annealing, which restrict their application in magnetic sensors and memory devices.
Innovation Solution
A magnetic structure comprising a coupling layer with a non-magnetic element like Ag, Cr, Ru, or Mo and a magnetic element like Ni, Co, or Fe, with a specific atomic ratio, allowing for non-collinear or antiferromagnetic coupling at various angles, and the ability to withstand annealing temperatures without losing coupling strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If PtMn coupling layers with thickness less than 10 nm are used to achieve non-collinear coupling, then the coupling strength is weak and saturation fields are low, but the structure size is reduced
Solution Approach 1:
The patent changes the compositional parameters of the coupling layer by using RuFe alloys with specific atomic ratios (x=1-50) instead of conventional PtMn. This parameter change enables achieving both thin thickness (reduced volume) and high coupling strength simultaneously, resolving the contradiction between miniaturization and coupling strength.
Solution Approach 2:
The patent employs composite material RuFe combining ruthenium (non-magnetic) and iron (magnetic) elements. This composite structure provides enhanced coupling strength compared to PtMn while maintaining thin layer thickness, effectively resolving the contradiction between reduced volume and maintained/strengthened coupling strength.
2Shape
If PtMn coupling layers are used for non-collinear coupling, then orthogonal coupling at 90° is achieved, but the coupling reverts to 0° after annealing at temperatures greater than 200°C
Solution Approach 1:
The patent modifies the compositional parameters by using RuFe alloys with controlled atomic ratios and introduces annealing temperature parameters (200-400°C) as processing conditions. These parameter changes enable the coupling structure to maintain non-collinear orientation after annealing, resolving the stability issue that plagues PtMn systems.
Solution Approach 2:
The patent employs a processing approach where controlled annealing is used to stabilize the RuFe coupling layer, effectively making the structure more resistant to thermal degradation. This resolves the issue of coupling reversal after annealing that occurs in PtMn systems.
3Ease of manufacture
If conventional coupling layers are used, then manufacturing is simpler, but the ability to sense strong external magnetic fields is limited
Solution Approach 1:
The patent changes the material composition parameters to RuFe alloys with specific atomic ratios, which provide enhanced saturation fields and magnetic sensing capability while remaining compatible with standard sputtering fabrication processes. This resolves the contradiction between manufacturing simplicity and improved measurement precision.
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 provides magnetic structures with enhanced coupling strength and stability, enabling the sensing of stronger external magnetic fields and maintaining non-collinear or antiferromagnetic coupling after annealing, thus improving the performance of magnetic sensors and memory devices.
Implementation Method 1
coupling layers for coupling magnetization directions of two or more spaced apart magnetic layers... The coupling layer may comprise at least one non-magnetic element and at least one magnetic element... causing the first magnetic layer to be non-collinearly coupled to the second magnetic layer
Implementation Method 2
Annealing may also be required to align antiferromagnetic layers in particular applications. There is a general desire for magnetic structures comprising two or more magnetic layers that are coupled via an intervening coupling layer where the magnetic structure, or a portion thereof may be annealed
Implementation Method 3
For magnetoresistive sensor applications, such as those employing tunnel-magnetoresistance (TMR) or giant-magnetoresistance (GMR)...
Implementation Method 4
For magnetoresistive sensor applications, such as those employing tunnel-magnetoresistance (TMR) or giant-magnetoresistance (GMR)...
Data Source
AI summary
A magnetic structure is provided. The magnetic structure may have a first magnetic layer with a first magnetization direction, a second magnetic layer with a second magnetization direction and a coupling layer interposed between the first and second magnetic layers. The coupling layer may include at least one non-magnetic element and at least one magnetic element. The atomic ratio of the at least one non-magnetic element to the at least one magnetic element is (100−x):x, where x is an atomic concentration parameter. Atomic concentration parameter, x, may cause the first magnetic layer to be non-collinearly coupled to the second magnetic layer such that, in the absence of external magnetic field, the first magnetization direction is oriented at a non-collinear angle relative to the second magnetization direction.