Magnetic Memory Device Domain Wall Control
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Solution Overview
Problem
Current magnetic memory devices face challenges in increasing storage density due to limitations in the movement and control of domain walls within magnetic wires.
Innovation Solution
The magnetic memory device incorporates a first magnetic portion with an extension portion and a third portion, along with electrodes and nonmagnetic portions, where the controller sets specific potentials to write information and shift magnetic domains, optimizing the configuration to enhance storage density by reducing the number of interconnects and controlling magnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional magnetic wire structures are used, then device simplicity is maintained, but storage density cannot be increased
Solution Approach 1:
The magnetic wire is divided into multiple magnetic portions (first magnetic portion, second magnetic portion, third magnetic portion) with distinct functions. Each portion can be independently controlled by dedicated electrodes, enabling multiple storage locations within a single wire structure and thereby increasing storage density without proportionally increasing overall device complexity
Solution Approach 2:
The patent introduces a vertical stacking dimension by positioning magnetic portions at different heights (first magnetic portion at first height, second magnetic portion at second height, third magnetic portion at third height). This multi-layer configuration allows multiple storage locations to be stacked vertically, dramatically increasing storage density without expanding the planar footprint
2Quantity of substance
If multiple electrodes are added to control domain walls, then storage density increases, but device complexity increases
Solution Approach 1:
Each magnetic portion is equipped with dedicated write electrodes and read electrodes that can perform multiple functions. The same electrode structure is used across different magnetic portions, and each electrode can participate in both write operations (generating spin current to move domain walls) and read operations (detecting magnetization state), reducing the need for separate specialized interconnects
Solution Approach 2:
The patent combines the write and read functions into a unified electrode system. The first and second electrodes serve both as write electrodes (applying current to move domain walls) and as read electrodes (detecting resistance changes to read stored information), thereby reducing the total number of interconnects needed while maintaining high storage density
3Reliability
If domain wall movement is used for information storage, then non-volatile memory is achieved, but control precision is insufficient
Solution Approach 1:
The magnetic wire is designed with different magnetic portions having locally optimized properties. Each magnetic portion can have tailored magnetic anisotropy, saturation magnetization, and damping characteristics to facilitate precise domain wall nucleation, propagation, and stabilization at specific locations, thereby improving control precision while maintaining non-volatile storage
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 allows for increased storage density by effectively writing, reading, and shifting magnetic domains, thereby improving the overall performance of the magnetic memory device.
Implementation Method 1
In a first operation of writing information to the third portion, the controller sets the first electrode to a first potential, sets the second electrode to a second potential, and sets the third electrode to a third potential. In a second operation of shifting magnetic domains of the extension portion, the controller sets the first electrode to the first potential, sets the second electrode to a fourth potential, and sets the third electrode to a fifth potential.
Data Source
AI summary
According to one embodiment, a magnetic memory device includes a first magnetic portion, a first electrode, a second electrode, a third electrode, a second magnetic portion, a first nonmagnetic portion, and a controller. The first magnetic portion includes an extension portion and a third portion. The extension portion includes a first portion and a second portion. The third portion is connected to the second portion. The first electrode is electrically connected to the first portion. At least a portion of the third portion is positioned between the second electrode and the third electrode. The second magnetic portion is provided between the second electrode and the at least a portion of the third portion. The first nonmagnetic portion is provided between the second magnetic portion and the at least a portion of the third portion. The controller is electrically connected to the first, second electrode, and third electrodes.