Current Injection Magnetic Domain Wall Motion Device
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing integration density of magnetic nonvolatile solid-state memories due to microfabrication leads to higher demagnetization fields, necessitating stronger external magnetic fields to reverse magnetization directions, resulting in increased electricity consumption.
Innovation Solution
A current injection-type magnetic domain wall-motion device with a microjunction structure comprising magnetic semiconductor bodies, where the magnetization direction is controlled by applying a pulse current across microjunction interfaces, allowing magnetic domain walls to move without requiring external magnetic fields, utilizing (Ga, Mn)As or (In, Mn)As ferromagnetic semiconductors with specific coercive force differences and configurations to minimize energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If microfabrication is used to increase integration density, then integration density is improved, but external magnetic field intensity requirement increases
Solution Approach 1:
The patent replaces the mechanical approach of applying external magnetic fields with a current injection method. A current is applied through the microjunction structure, generating a spin-polarized current that exerts a torque on the magnetic moments, enabling magnetization reversal without external magnetic fields. This substitution of the actuation mechanism directly resolves the contradiction by eliminating the need for high external magnetic fields while maintaining high integration density.
Solution Approach 2:
The patent changes the control parameter from external magnetic field strength to current density. By adjusting the current density applied through the microjunction, the magnetization state can be switched between parallel and antiparallel configurations. This parameter change enables precise control of magnetization reversal in miniaturized structures without requiring proportionally increasing external magnetic fields.
2Reliability
If external magnetic fields are strengthened to reverse magnetization, then magnetization reversal is achieved, but electricity consumption increases
Solution Approach 1:
The patent replaces energy-intensive external magnetic field generation with electrical current injection. The current flows through the microjunction, utilizing spin-transfer torque or spin-orbit coupling mechanisms to reverse magnetization. This substitution dramatically reduces power consumption because the energy is delivered directly to the magnetic moments through electron spin interactions rather than requiring large-scale magnetic field generation across the entire device.
Solution Approach 2:
The patent introduces a current-carrying microjunction structure as an intermediary between the power source and the magnetic bodies. This intermediary delivers energy efficiently through spin-polarized electrons that directly interact with the magnetic moments, reducing energy loss compared to generating external magnetic fields that would require substantial power and suffer from field leakage and inefficiency.
3Reliability
If magnetic domain wall is created in third magnetic body, then magnetization control is achieved, but energy loss increases
Solution Approach 1:
The patent creates a magnetic domain wall specifically in the third magnetic body with distinct magnetic properties, rather than throughout the entire structure. The third magnetic body is designed with specific characteristics (such as different magnetization direction or coercivity) that facilitate domain wall formation and movement. This localized approach allows magnetization control while minimizing the volume over which energy is dissipated, reducing overall energy loss compared to controlling magnetization throughout larger magnetic structures.
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 magnetization direction reversal with low power consumption and no external magnetic fields, enhancing integration density and reducing energy loss in magnetic domain wall creation.
Implementation Method 1
a magnetic domain wall is moved by the interaction between the magnetic domain wall and the current in the same direction as that of the current or in the direction opposite to that of the current
Implementation Method 2
The magnetic bodies are made of a magnetic semiconductor... the magnetic semiconductor is a (Ga, Mn)As ferromagnetic semiconductor... the magnetic semiconductor is an (In, Mn)As ferromagnetic semiconductor
Data Source
AI summary
The present invention provides a current injection-type magnetic domain wall-motion device which requires no external magnetic field for reversing the magnetization direction of a ferromagnetic body and which has low power consumption. The current injection-type magnetic domain wall-motion device includes a microjunction structure including two magnetic bodies (a first magnetic body 1 and a second magnetic body 2) having magnetization directions antiparallel to each other and a third magnetic body 3 sandwiched therebetween. The magnetization direction of the device is controlled in such a manner that a pulse current (a current density of 104-107 A/cm2) is applied across junction interfaces present in the microjunction structure such that a magnetic domain wall is moved by the interaction between the magnetic domain wall and the current in the same direction as that of the current or in the direction opposite to that of the current.