Magnetic Memory Domain Wall Injection via Non-Magnetic Pattern

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Solution Overview

Problem

Current magnetic memory devices face challenges in efficiently injecting a magnetic domain wall into a magnetic track with a synthetic antiferromagnetic structure, which is crucial for high-speed and low-power operations.

Innovation Solution

A magnetic memory device and method that includes a conductive line with a magnetic track comprising a lower magnetic layer, a spacer layer, and an upper magnetic layer, where a non-magnetic pattern overlaps with the lower magnetic layer, allowing for antiferromagnetic coupling. An external magnetic field is applied to reverse the magnetization direction and form a magnetic domain wall, which is then injected into the synthetic antiferromagnetic region using a current through the conductive line.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a magnetic track with synthetic antiferromagnetic structure is used, then high-speed and low-power operation is achieved, but difficulty in injecting magnetic domain wall occurs

Engineering Contradiction:

Improveoperation speedVSAvoidease of injecting magnetic domain wall

Core Design Contradiction:

SpeedVSEase of operation

Solution Approach 1:

The magnetic track is segmented into distinct regions: a ferromagnetic region with a non-magnetic pattern that facilitates domain wall formation, and a synthetic antiferromagnetic region for stable data storage. This segmentation allows the track to simultaneously achieve high-speed operation through the SAF structure while enabling easy domain wall injection through the ferromagnetic region with the non-magnetic pattern that creates a domain wall nucleation site.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The non-magnetic pattern acts as an intermediary element between the applied magnetic field and the magnetic layers. It creates a localized region where domain walls can form more easily by modifying the magnetic field distribution, thereby facilitating domain wall injection into the synthetic antiferromagnetic track without requiring excessive external magnetic field strength.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If external magnetic field is applied to reverse magnetization direction, then magnetic domain wall is formed, but additional device complexity is introduced

Engineering Contradiction:

Improvemagnetic domain wall formationVSAvoidexternal magnetic field application system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of applying a uniform external magnetic field across the entire device, the non-magnetic pattern creates a localized region with modified magnetic properties. This local quality change allows domain wall formation to occur more easily in a specific region, reducing the overall magnetic field strength required and simplifying the external field application system.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The non-magnetic pattern is pre-formed in the device structure to create a favorable environment for domain wall nucleation. This preliminary action prepares the magnetic track in advance, so that when an external magnetic field is applied, domain walls form readily in the predetermined region without requiring complex real-time control systems.

Inventive Principle:

Principle #10Preliminary action

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 easy injection of a magnetic domain wall into the magnetic track, facilitating the initialization of the memory device and improving its operational efficiency and speed.

Implementation Method 1

The lower magnetic layer and the upper magnetic layer may be antiferromagnetically coupled to each other by the spacer layer

Methodology Applied

Scientific EffectAntiferromagnetic coupling: Magnetism

Implementation Method 2

applying a first external magnetic field to the magnetic track to reverse the initial magnetization direction of the portion of the lower magnetic layer which vertically overlaps with the non-magnetic pattern

Methodology Applied

Scientific EffectMagnetization reversal: Magnetic Field

Implementation Method 3

applying a current to the conductive line to inject the lower magnetic domain wall into the lower magnetic layer in the synthetic antiferromagnetic region

Methodology Applied

Scientific EffectSpin transfer torque:

Data Source

PatentUS20230165158A1Magnetic memory devices and methods for initializing the same

Publication Date: 2023.05.25 SAMSUNG ELECTRONICS CO LTD

AI summary

A magnetic memory device includes a conductive line extending in a first direction, and a magnetic track extending in the first direction on the conductive line. The magnetic track includes a lower magnetic layer, a spacer layer and an upper magnetic layer sequentially stacked on the conductive line, and a non-magnetic pattern on the spacer layer and adjacent a side of the upper magnetic layer. The non-magnetic pattern vertically overlaps with a portion of the lower magnetic layer. The lower magnetic layer and the upper magnetic layer are antiferromagnetically coupled to each other by the spacer layer.