Spin Valve Element With Synchronized Microwave Oscillation
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Solution Overview
Problem
Current spin valve elements face challenges in achieving high-output microwave oscillation due to size limitations, high manufacturing costs, and impedance matching issues, which restrict their practical application in spin electronics.
Innovation Solution
The integration of multiple spin valve elements in series and parallel connections, along with the use of porous insulating layers formed through nanoimprinting or anodic oxidation, allows for impedance matching and synchronized oscillation, reducing manufacturing costs and enhancing output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the size of magnetic layers is reduced to suppress exchange coupling, then microwave oscillation output is improved, but manufacturing precision requirements increase and costs rise
Solution Approach 1:
The patent divides the spin valve element into multiple magnetic layers (first ferromagnetic layer, second ferromagnetic layer, third ferromagnetic layer) with distinct functions. The first and second layers form the spin valve structure for microwave oscillation, while the third layer serves as a reference layer. This segmentation allows optimization of each layer's thickness and properties independently, enabling high output at 150 nm or less without compromising manufacturing precision.
Solution Approach 2:
Different magnetic layers are assigned different local properties: the first ferromagnetic layer has perpendicular magnetic anisotropy for spin polarization, the second layer has in-plane magnetization for oscillation, and the third layer has perpendicular anisotropy for reference. The insulating layer thickness is locally optimized at 3-5 nm to balance tunneling current for high output while preventing exchange coupling leakage. This local quality differentiation resolves the contradiction between small size and precision control.
2Power
If multiple spin valve elements are integrated to increase output, then microwave power is improved, but device complexity and impedance matching difficulty increase
Solution Approach 1:
The patent merges multiple spin valve elements into a single integrated structure where first ferromagnetic layers from different elements are coupled to a common second ferromagnetic layer. This merging approach allows multiple elements to oscillate in synchronization, achieving high output power while simplifying the overall device structure and impedance matching compared to separate integrated elements.
Solution Approach 2:
The second ferromagnetic layer acts as an intermediary that couples the first ferromagnetic layers from multiple spin valve elements. This intermediary layer enables synchronized oscillation and facilitates impedance matching by providing a common magnetic coupling path, thereby reducing the complexity of integrating multiple elements while achieving high power output.
3Power
If insulating layer thickness is reduced to increase tunneling current, then microwave output is improved, but exchange coupling leakage increases
Solution Approach 1:
The patent optimizes the insulating layer thickness to a specific parameter range of 3-5 nm, which is thin enough to allow sufficient tunneling current for high microwave output but thick enough to suppress exchange coupling leakage between magnetic layers. This precise parameter control resolves the contradiction between increasing tunneling current and preventing harmful exchange coupling.
4Ease of manufacture
If conventional photolithography is used for manufacturing, then manufacturing cost is reduced, but achievable feature size is limited to approximately 150 nm or less
Solution Approach 1:
The patent uses photolithography with positive resist to selectively remove portions of the insulating layer, creating a patterned structure where the insulating layer is partially removed to expose underlying magnetic layers in specific regions. This partial action approach allows conventional photolithography to achieve the required 150 nm or less feature sizes by optimizing the exposure and development parameters, thereby reducing manufacturing cost while meeting precision requirements.
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 approach enables the creation of high-output microwave oscillators with adjusted impedance, suppressing transmission losses and achieving synchronized oscillation across multiple elements, significantly improving output compared to conventional single-element systems.
Implementation Method 1
In order to suppress the exchange coupling due to the leakage magnetic field from the film edge portions of the ferromagnetic layers
Implementation Method 2
When electrons are passed from the fixed layer 23 toward the free layer 25 in this element, a torque acts to cause the magnetization of the free layer 25 to be aligned parallel to the direction of the magnetization of the fixed layer 23
Implementation Method 3
spin valve elements utilizing the tunneling magneto-resistance (TMR) effect occurring in a layered structure of a ferromagnetic layer, an insulating layer, and a ferromagnetic layer
Implementation Method 4
spin valve elements utilizing the giant magneto-resistance (GMR) effect occurring in a layered structure of a ferromagnetic layer, nonmagnetic layer (conducting layer), and a ferromagnetic layer
Data Source
AI summary
A spin valve element may include a plurality of magnetic element groups. Each magnetic element group may be formed, at least in part, by a plurality of magnetic elements being connected in parallel. Each magnetic element may include an intermediate layer and a pair of ferromagnetic layers sandwiching the intermediate layer. The plurality of magnetic element groups may be connected together in series or in parallel. The plurality of magnetic elements may be configured to undergo a microwave oscillation and are placed in proximity sufficient that oscillation signals are configured to be generated with the magnetic elements mutually synchronized. The proximity may include a range equal to a wavelength of the microwave oscillation.