Hybrid Storage Layer Spintronic Device for Low Switching Current
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Solution Overview
Problem
Spintronic devices face a trade-off between low switching current and high retention, with existing designs either increasing device thickness or reducing tunnel magnetoresistance, making it challenging to achieve both small size and low power consumption.
Innovation Solution
A spintronic device with a hybrid storage layer comprising multiple magnetic layers and a metal layer that provides intrinsic perpendicular magnetic anisotropy and spin transfer torque, along with a metal layer acting as a spin sink to enhance switching efficiency and decouple the storage layer from fixed magnetic layers, allowing for additional torque generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a double MTJ design is adopted to reduce switching current, then switching current is reduced, but device thickness increases and resistance increases
Solution Approach 1:
The patent combines a CoFeB layer and a Co layer into a single hybrid storage layer that is exchange-coupled, merging the benefits of both materials (low damping from CoFeB and high PMA from Co) without requiring a second tunnel junction. This eliminates the thickness increase associated with double MTJ designs while maintaining reduced switching current through the composite magnetic structure.
Solution Approach 2:
The invention uses a composite hybrid storage layer comprising CoFeB and Co layers with different magnetic properties. The CoFeB layer provides low damping for efficient spin transfer torque, while the Co layer contributes high perpendicular magnetic anisotropy. This composite structure achieves low switching current without the thickness penalty of double MTJ designs.
2Use of energy by moving object
If a double MTJ design is adopted to reduce switching current, then switching current is reduced, but tunnel magnetoresistance decreases
Solution Approach 1:
The patent merges the functionality of two separate magnetic layers into a single hybrid storage layer that maintains strong exchange coupling. This allows the structure to generate multiple torque terms for reduced switching current while preserving a single high-quality MgO tunnel junction, thereby maintaining high TMR.
Solution Approach 2:
The hybrid storage layer combines CoFeB and Co materials to achieve both low switching current and high TMR. The CoFeB layer contributes to low damping and efficient switching, while the Co layer enhances perpendicular anisotropy, together enabling reduced switching current without compromising the TMR of the single tunnel junction.
3Reliability
If intrinsic perpendicular magnetic anisotropy material is incorporated to boost retention, then retention is improved, but device complexity increases
Solution Approach 1:
The patent merges the retention-enhancing PMA material (Co layer) with the low-damping CoFeB layer into a single hybrid structure with exchange coupling. This integrated design achieves high retention through intrinsic PMA while avoiding the complexity of separate retention and switching layers or additional tunnel junctions.
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 enables efficient switching with reduced switching current while maintaining high retention characteristics, avoiding the thickness and resistance issues of previous designs, thus achieving a balance between device size and power consumption.
Implementation Method 1
The first magnetic layer of the hybrid storage layer may be configured to provide the tunnel magnetoresistance (TMR) effect for device read
Implementation Method 2
The first magnetic layer of the hybrid storage layer may be configured to provide the spin transfer torque (STT) effect for device write
Implementation Method 3
The spacer layer of the hybrid storage layer may be configured to provide a texture breaking between the different crystallographic orientations of the first magnetic layer and the second magnetic layer, respectively
Implementation Method 4
a metal layer acting as a spin sink to enhance switching efficiency and decouple the storage layer from fixed magnetic layers, allowing for additional torque generation
Implementation Method 5
a hybrid storage layer allows for incorporating intrinsic perpendicular magnetic anisotropy (PMA) material such as Co or Co/Pt laminates, that can significantly boost the retention
Data Source
AI summary
The disclosed technology relates generally to a magnetic device and more particularly to a spintronic device comprising a tunnel barrier, a hybrid storage layer on the tunnel barrier and a metal layer on the hybrid storage layer. The hybrid storage layer comprises a first magnetic layer, a spacer layer on the first magnetic layer and at least one further magnetic layer on the spacer layer and exchange coupled to the first magnetic layer via the spacer layer.