Skyrmion Memory Transverse Current Transfer

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Solution Overview

Problem

Current magnetic shift registers require high currents and have low transfer velocities for magnetic domain walls, leading to slow memory writing and reading times, and existing skyrmion transfer methods are not suitable for non-volatile memory due to low current density and lack of practical implementation.

Innovation Solution

A magnetic element with a skyrmion memory configuration where the transfer direction is perpendicular to the current direction, allowing for efficient skyrmion transfer and storage using a chiral magnet with stable positions and a magnetic field generating unit, enabling fast and non-volatile data storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If magnetic domain walls are driven by current in conventional magnetic shift registers, then information transfer is achieved, but large current is required and transfer velocity is low

Engineering Contradiction:
Improvetransfer velocityVSAvoidcurrent consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The invention changes the fundamental parameter of information carrier from magnetic domain walls to skyrmions, which have different transport properties. Skyrmions can be moved by much smaller currents compared to domain walls, directly resolving the contradiction between transfer velocity and current consumption.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces the conventional current-driven domain wall motion mechanism with a skyrmion-based mechanism that utilizes spin-transfer torque and Dzyaloshinskii-Moriya interaction, substituting the mechanical domain wall displacement with quantum-mechanical skyrmion transport that is more energy-efficient.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Speed

If skyrmions are transferred in longitudinal arrangement (current parallel to transfer direction), then transfer is achieved, but resistance is large and current density is restricted

Engineering Contradiction:
Improveskyrmion transfer velocityVSAvoidcurrent density capability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The invention changes the transfer arrangement from longitudinal (current parallel to transfer direction) to transverse (current perpendicular to transfer direction). This dimensional change allows current to flow across the width of the nanowire rather than along its length, dramatically reducing the resistance and enabling high current density for fast skyrmion transfer.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Speed

If steady-state current is used for skyrmion transfer, then transfer is achieved, but memory cannot be non-volatile

Engineering Contradiction:
Improveskyrmion transfer speedVSAvoiddata retention without power
Core Design Contradiction:
SpeedVSDuration of action of stationary object

Solution Approach 1:

The invention uses periodic pulsed current instead of steady-state current to transfer skyrmions. The pulsed nature allows skyrmions to be moved during write operations while enabling the memory to enter a low-power state for data retention, achieving both fast transfer and non-volatility.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The invention extracts the skyrmion from the current path after transfer, allowing the current to be switched off while the skyrmion (and its stored information) remains intact in the magnet. This separation enables non-volatile storage independent of continuous power supply.

Inventive Principle:
Principle #2Taking out (Extraction)

4Length of moving object

If fine line structure with nanoscale width is used, then skyrmion transfer arrangement is achieved, but resistance between end portions becomes large

Engineering Contradiction:
Improvenanoscale dimensionVSAvoidresistance loss
Core Design Contradiction:
Length of moving objectVSLoss of energy

Solution Approach 1:

The invention changes the current flow direction from longitudinal (along the length of the nanowire) to transverse (across the width). This dimensional change bypasses the resistance problem inherent in long, narrow structures by using the width dimension for current flow, significantly reducing resistive losses.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 enables rapid skyrmion transfer and storage, overcoming the limitations of existing technologies by achieving high-speed, low-power, and non-volatile memory operations, with the ability to overwrite information quickly and efficiently.

Implementation Method 1

A skyrmion is a nanoscale magnetic texture in which a magnetic moment has a spiral texture

Methodology Applied
Scientific EffectSkyrmion formation: Magnetic Field

Implementation Method 2

by causing a current to transfer a skyrmion to flow through the magnet, the skyrmion is transferred

Methodology Applied
Scientific EffectSpin transfer torque:

Data Source

PatentEP3214663B1Magnetic device, skyrmion memory, skyrmion memory device, solid-state electronic device equipped with skyrmion memory, data recording device, data processing device, and communication device
Publication Date: 2021.11.03 RIKEN CO LTD
  • EP3214663B1 patent drawingFigure 1
  • EP3214663B1 patent drawingFigure 2(a)~2(e)
  • EP3214663B1 patent drawingFigure 3

AI summary

To provide a magnetic element capable of performing skyrmion transfer, a skyrmion memory to which this magnetic element is applied, and a shift register, for example, a magnetic element capable of performing skyrmion transfer is provided, the magnetic element providing a transverse transfer arrangement in which the skyrmion is transferred substantially perpendicular to a current between an upstream electrode and a downstream electrode, and including a plurality of stable positions in which the skyrmion exists more stably than in other regions of a magnet, and a skyrmion sensor that detects a position of the skyrmion.