Orthogonal Biasing Layer for Magnetic Stack Stability
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Solution Overview
Problem
Magnetic memory stacks face challenges with reduced size leading to magnetic instability, high programming current, and thermal instability, affecting data storage accuracy and scalability in data storage devices.
Innovation Solution
A magnetic stack configuration with a magnetically free layer and a reference structure aligned along a common plane, and a biasing layer aligned orthogonally, utilizing a biasing layer to increase magnetic stability and minimize programming current, along with tuning anisotropy and using materials like FePt and CoPt for high coercivity, and a flux concentration feature to redirect magnetic flux efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the magnetic stack size is reduced to increase storage density, then storage capacity is improved, but magnetic stability deteriorates
Solution Approach 1:
The patent introduces a biasing layer with magnetization oriented perpendicular to the plane of the magnetically free layer and reference structure. This orthogonal orientation in a different dimension provides magnetic stability without increasing the lateral footprint of the stack, thus maintaining high storage density while improving magnetic stability.
Solution Approach 2:
The magnetic stack employs a composite structure consisting of multiple layers with different magnetic properties: a magnetically free layer, a reference structure, and a biasing layer with perpendicular magnetization. This composite configuration combines the benefits of each layer to achieve both high density and enhanced stability.
2Device complexity
If conventional magnetic stack configuration is used, then structure is simple, but programming current is high
Solution Approach 1:
By adding a biasing layer with perpendicular magnetization orientation, the patent creates an orthogonal magnetic field that assists in switching the magnetization of the free layer. This dimensional addition reduces the current required for programming while maintaining structural simplicity through sequential layer deposition.
Solution Approach 2:
The biasing layer acts as an intermediary that provides an auxiliary magnetic field to assist in the switching process. This intermediary layer reduces the energy barrier for magnetization switching, thereby lowering the programming current requirement without significantly complicating the overall structure.
3Quantity of substance
If magnetic stack size is reduced, then storage density is improved, but thermal stability deteriorates
Solution Approach 1:
The composite structure with perpendicular biasing layer creates additional magnetic anisotropy that enhances thermal stability. The orthogonal magnetization orientation provides a stabilizing energy barrier that prevents thermal fluctuations from causing unwanted switching, enabling stable operation at smaller dimensions.
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 enhances magnetic and thermal stability while reducing programming current, enabling scalable and stable data storage in high-density devices by offsetting demagnetization fields and optimizing magnetic flux redirection.
Implementation Method 1
a biasing layer having a third magnetization aligned along a second plane, substantially perpendicular to the first plane
Implementation Method 2
tuning anisotropy of the magnetically free layer to stabilize thermal stability
Data Source
AI summary
Various embodiments may configure a magnetic stack with a magnetically free layer, a reference structure, and a biasing layer. The magnetically free layer and reference structure can each be respectively configured with first and second magnetizations aligned along a first plane while the biasing layer has a third magnetization aligned along a second plane, substantially perpendicular to the first plane.