Antiferromagnetically Coupled Magnetic Track for Low-Current Domain Motion
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Solution Overview
Problem
Existing memory devices face challenges in achieving fast operating speed and low power consumption while maintaining non-volatility and reduced latency, particularly in efficiently moving magnetic domains and improving tunnel magnetoresistance characteristics.
Innovation Solution
A magnetic memory device with a magnetic track line comprising lower and upper magnetic layers antiferromagnetically coupled by an exchange coupling layer, and a spacer layer to enhance domain movement efficiency and tunnel magnetoresistance, utilizing materials with specific crystal textures to optimize magnetic anisotropy and coupling strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional magnetic memory structures are used, then device simplicity is maintained, but domain movement efficiency is insufficient and high current is required
Solution Approach 1:
The magnetic track line is segmented into multiple magnetic layers (first magnetic layer, second magnetic layer, third magnetic layer) with distinct functions. The first and third layers provide magnetic anisotropy and domain wall pinning, while the second layer enables domain wall movement. This segmentation allows efficient domain movement with reduced current requirements by optimizing each layer's contribution to the overall magnetic structure.
Solution Approach 2:
The patent employs composite magnetic structures combining multiple ferromagnetic layers with different magnetic properties (perpendicular magnetic anisotropy in first and third layers, in-plane magnetic anisotropy in second layer) coupled through non-magnetic spacer layers. This composite approach enhances domain movement efficiency by leveraging the synergistic effects of different magnetic anisotropy types and reducing the critical current density required for domain wall propagation.
2Productivity
If magnetic layers are added to improve domain movement efficiency, then domain movement efficiency improves, but device structure becomes more complex
Solution Approach 1:
Multiple magnetic layers are merged into a single integrated magnetic track line structure that functions as one unified component. The first, second, and third magnetic layers are combined with non-magnetic spacer layers to form a stacked configuration that achieves enhanced domain movement efficiency while maintaining structural coherence and avoiding the need for separate discrete components.
Solution Approach 2:
The patent transitions from a conventional planar magnetic structure to a vertically stacked multi-layer configuration. By adding the vertical dimension with multiple magnetic layers separated by non-magnetic spacers, the device achieves improved domain movement efficiency through enhanced magnetic anisotropy and domain wall pinning effects without significantly increasing lateral footprint or overall device complexity.
3Reliability
If conventional reading device structures are used, then device simplicity is maintained, but tunnel magnetoresistance characteristics are insufficient
Solution Approach 1:
The reading device employs a magnetic tunnel junction with locally optimized structures including specific barrier layer thicknesses, magnetization orientations, and material compositions tailored to maximize tunnel magnetoresistance. The pinned layer and free layer are configured with distinct magnetic properties and spatial arrangements that enhance the TMR effect for reliable data reading while maintaining a compact junction structure.
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 movement of magnetic domains with reduced current requirements and improves tunnel magnetoresistance, allowing stable and efficient reading operations with enhanced data storage capabilities.
Implementation Method 1
an exchange coupling layer between the lower and upper magnetic layers... The lower and upper magnetic layers may be antiferromagnetically coupled with each other by the exchange coupling layer
Implementation Method 2
A magnetic memory device may include a conductive line extended in a first direction, a magnetic track line provided on the conductive line... the direction of the movement of the magnetic domains in the magnetic track line is changed depending on the direction of a current
Data Source
AI summary
A magnetic memory device includes a conductive line extended in a first direction, a magnetic track line provided on the conductive line and extended in the first direction, and a non-magnetic line provided on the magnetic track line and extended in the first direction. The magnetic track line includes a lower magnetic layer and an upper magnetic layer stacked on the conductive line, an exchange coupling layer between the lower and upper magnetic layers, and a spacer layer between the exchange coupling layer and the upper magnetic layer. The exchange coupling layer is in contact with a bottom surface of the spacer layer, and the lower and upper magnetic layers are antiferromagnetically coupled with each other by the exchange coupling layer.