Nonvolatile Magnetic Logic Device With Isolated Read Write Paths
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Solution Overview
Problem
Current semiconductor technologies face challenges in developing commercially viable magnetic logic devices that offer low energy, nonvolatile operation and reduced production costs for digital circuits.
Innovation Solution
A nonvolatile magnetic logic device with electrically isolated read and write paths, utilizing a magnetic layer with a uniform magnetization direction that can be switched between two stable single-domain logic states, represented by the direction of magnetization, and evaluated using a read path with magnetic tunnel junctions and synthetic antiferromagnetic layers for efficient logic state representation and evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If magnetic logic devices are developed using current semiconductor technologies, then production costs can be reduced, but achieving low energy nonvolatile operation and commercial viability remains challenging
Solution Approach 1:
The device is divided into separate read path and write path that are electrically isolated but magnetically coupled. This segmentation allows independent optimization of read and write operations, enabling low-energy nonvolatile operation while maintaining manufacturing compatibility with existing semiconductor processes
Solution Approach 2:
An electrically insulating layer is introduced as an intermediary between the read path and write path. This layer provides electrical isolation while allowing magnetic coupling through it, enabling nonvolatile logic state retention without requiring continuous power supply to both paths simultaneously
2Reliability
If electrically insulating layer is used to isolate read and write paths, then electrical isolation is achieved, but magnetic coupling efficiency may be reduced
Solution Approach 1:
The magnetic anisotropy of the free layer is engineered to be perpendicular to the film plane, creating a uniaxial magnetic anisotropy that enhances magnetic coupling through the insulating layer. By carefully controlling the thickness and material composition of the insulating layer, optimal magnetic coupling is achieved while maintaining electrical isolation
3Duration of action of stationary object
If magnetic layer switching is used for logic state representation, then nonvolatile operation is achieved, but switching energy and speed may be limited
Solution Approach 1:
The device utilizes magnetization direction reversal as a phase transition between two stable single-domain states. The perpendicular magnetic anisotropy enables abrupt switching between parallel and antiparallel magnetization states, achieving both nonvolatile retention and fast switching speeds suitable for logic circuit applications
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
Enables low-energy, high-speed switching with reduced production costs by maintaining logic states without power and allowing for efficient logic state evaluation, suitable for logic circuit applications.
Implementation Method 1
The magnetic layer may be switched between two stable single-domain logic states by passing a current through the magnetic layer of the write-path
Implementation Method 2
The electrically insulating layer promotes electrical isolation between the read path and the write path and magnetic coupling of the read path to the write path
Implementation Method 3
The read path further comprises at least one magnetic tunnel junction (MTJ) that comprises a reference layer having at least one fixed magnetization direction, a free layer having a switchable magnetization direction
Implementation Method 4
The read path further comprises a synthetic antiferromagnetic layer that pins the at least one fixed magnetization direction of the reference layer of the at least one MTJ
Data Source
AI summary
In one aspect, a nonvolatile magnetic logic device comprises an electrically insulating layer, a write path, and a read path. The write path comprises a plurality of write path terminals and a magnetic layer having a uniform magnetization direction that is indicative of a direction of magnetization of the magnetic layer in a steady state. A logic state is written to the nonvolatile magnetic logic device by passing a current through the plurality of write path terminals. The read path comprises a plurality of read path terminals for evaluation of the logic state. The electrically insulating layer promotes electrical isolation between the read path and the write path and magnetic coupling of the read path to the write path.