Hybrid Free Layer With Oxidized Edge Coupling
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Solution Overview
Problem
Magnetic memory devices face challenges in reducing the switching current required to change the magnetization state of magnetic tunnel junctions, which affects their thermal stability and efficiency.
Innovation Solution
A magnetic memory device with a hybrid free layer comprising a soft magnetic layer, a hard magnetic layer, and a coupling layer, where the coupling layer's edges are modified to reduce magnetic coupling by oxidizing a portion, thereby reducing the switching current needed to switch the magnetization orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a magnetic coupling layer is used between the hard magnetic layer and soft magnetic layer, then thermal stability is improved, but switching current increases
Solution Approach 1:
The coupling layer is designed with spatially varying magnetic properties: the center region contains magnetic material to provide thermal stability, while the edge region contains non-magnetic material to reduce switching current. This local differentiation allows the same layer to simultaneously achieve both thermal stability and low switching current requirements.
2Reliability
If the coupling layer comprises substantially all magnetic material, then thermal stability is maximized, but switching current is doubled compared to hybrid structure
Solution Approach 1:
The coupling layer is segmented into two distinct regions: a center section containing magnetic material and an edge section containing non-magnetic material. This segmentation allows independent optimization of each region's function - the center provides thermal stability while the edge reduces switching current requirements.
3Use of energy by moving object
If edge sections of coupling layer are made non-magnetic, then switching current is reduced by half, but magnetic coupling strength decreases
Solution Approach 1:
The coupling layer is designed with spatially varying magnetic properties: the center region contains magnetic material to provide thermal stability, while the edge region contains non-magnetic material to reduce switching current. This local differentiation allows the same layer to simultaneously achieve both thermal stability and low switching current 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
The solution effectively reduces the switching current by half, enhancing the thermal stability and efficiency of the magnetic memory device while maintaining the resistance-value differences for data storage.
Implementation Method 1
a coupling layer comprising a center, a first surface, a second surface and an edge extending between the first surface and the second surface in which a first section of the coupling layer between the center and a predetermined distance from the center comprises a magnetic material
Implementation Method 2
the second section of the coupling layer between the predetermined distance from the center to the edge comprises a non-magnetic material
Data Source
AI summary
A magnetic memory device and a method to make the device is disclosed. The magnetic memory device comprises a free magnetic layer that includes a hard magnetic material layer, a soft magnetic material layer and a coupling layer that is between the hard magnetic material layer and the soft magnetic material layer. The coupling layer comprises a magnetic material that has oxidized edges. In one embodiment, the magnetic material of the coupling layer comprises a Heusler alloy or a silicon-based magnetic material. A predetermined amount of the coupling layer is oxidized to controllably reduce the switching current Jc0 of the free magnetic layer to be about half of the switching current if the coupling layer comprised substantially all magnetic material and no oxide.