Non-volatile Logic Device Using Magnetic Domain Wall Motion
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Solution Overview
Problem
Existing non-volatile logic operation devices face challenges in achieving compact size and stable operation at room temperature, particularly due to limitations in spin-torque transfer efficiency and cell size, as well as the need for additional memory components in field programmable gate arrays (FPGAs).
Innovation Solution
A non-volatile logic operation device is designed with an operation unit connected to input and output terminals, featuring a ferromagnetic operation layer and a control unit that exerts magnetic interaction, allowing for both logic operations and memory functions within a compact form factor, utilizing domain wall motion and spin-torque transfer mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an FeRAM is used to replace SRAM, then non-volatile storage is achieved, but the number of rewrite operations is limited
Solution Approach 1:
The patent merges logic operation functionality and memory storage functionality into a single magnetic domain wall device. The same magnetic layer structure performs both logic computations and non-volatile data retention, eliminating the need for separate FeRAM components while achieving unlimited rewrite operations through domain wall manipulation.
Solution Approach 2:
The magnetic domain wall device serves multiple functions simultaneously: it performs logic operations (AND, OR, NOT gates) and stores data non-volatily in the same physical structure. The magnetization state of the domain wall serves both as computational state and memory state, providing universal functionality.
2Reliability
If an MRAM is used to replace SRAM, then non-volatile storage is achieved, but the cell size is large
Solution Approach 1:
The patent transitions from planar magnetization switching to three-dimensional domain wall motion along magnetic stripes. By confining magnetization changes to one-dimensional domain walls rather than two-dimensional magnetization reversal, the device achieves compact cell size while maintaining non-volatile storage capability.
Solution Approach 2:
The magnetic layer is segmented into distinct magnetic stripes that guide domain wall motion. This segmentation creates well-defined one-dimensional paths for domain walls, enabling precise control and compact device geometry compared to conventional MRAM cell structures.
3Adaptability or versatility
If a Spin MOSFET is used for non-volatile logic operation, then both logic and memory functions are integrated, but stable operation at room temperature is difficult due to low spin-torque transfer efficiency
Solution Approach 1:
The patent replaces the Spin MOSFET's spin-torque transfer mechanism with a magnetic field-driven domain wall motion mechanism. By using external magnetic fields to drive domain wall movement instead of relying on spin-polarized current transfer, the system achieves stable room temperature operation while maintaining logic-memory integration.
Solution Approach 2:
The patent changes the operational parameter from current-driven spin torque to field-driven domain wall motion. This parameter change enables stable room temperature operation by utilizing magnetic field effects that are more robust at elevated temperatures compared to spin-torque mechanisms.
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 device operates effectively at room temperature, integrating logic and memory functions, reducing the overall size and eliminating the need for additional memory components, thereby addressing the challenges of compactness and stability.
Implementation Method 1
a control unit that is connected to a third input terminal and that includes a control layer, the control unit being arranged in the vicinity of the operation unit... the control unit being arranged in a range where the control unit can exert a magnetic interaction on the operation unit
Implementation Method 2
an operation unit that is connected to a first input terminal, a second input terminal, and an output terminal, and that includes an operation layer... a first non-magnetic layer and a reference layer
Data Source
AI summary
A non-volatile logic operation device includes an operation unit that is connected to a first input terminal, a second input terminal, and an output terminal, includes an operation layer, a first non-magnetic layer, and a reference layer, and outputs from the output terminal a result of a logic operation on signals applied at the first input terminal and the second input terminal, and a control unit that is connected to a third input terminal, and includes a control layer. The control unit is arranged in the vicinity of the operation unit.