Magnetization Control Element with Exchange Coupled Magnetic Layers

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Solution Overview

Problem

Magnetoelectric control elements exhibit asymmetrical energy requirements for switching between two magnetization states, making stable data writing challenging due to differing energy needs for transitioning between easy-to-stabilize and hard-to-stabilize states.

Innovation Solution

A magnetization control element with a magnetoelectric material and a magnetic coupling layer, where the magnetization direction is imparted opposite to the magnetic coupling layer, and the exchange coupling is configured to balance energy requirements, ensuring symmetrical energy needs for state transitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a ferromagnet is made adjacent to the antiferromagnet through exchange coupling to transfer the magnetization state, then the magnetization state can be read, but the energy required for switching between two states becomes asymmetrical

Engineering Contradiction:

Improvemagnetization state readingVSAvoidswitching energy symmetry

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies asymmetry by intentionally introducing a unidirectional magnetization component in the antiferromagnet that compensates for the asymmetrical exchange coupling field. This creates a symmetrical energy landscape despite the inherent asymmetry in the ferromagnet-antiferromagnet coupling, allowing equal energy requirements for both switching directions while maintaining the ability to read the magnetization state through the coupled ferromagnet.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent changes the magnetization parameter of the antiferromagnet by imparting a specific unidirectional magnetization component. This parameter modification adjusts the energy landscape to achieve symmetrical switching energies, transforming the system from having asymmetrical energy requirements to symmetrical ones while preserving the readout functionality through exchange coupling.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If the antiferromagnet is aligned such that spins cancel their moments, then the internal magnetization state can be controlled, but the magnetization state cannot be externally output

Engineering Contradiction:

Improvespin alignment stabilityVSAvoidmagnetization state output

Core Design Contradiction:

Stability of the object's compositionVSLoss of information

Solution Approach 1:

The patent uses a ferromagnet as an intermediary layer between the antiferromagnet and the external environment. The ferromagnet couples to the antiferromagnet through exchange coupling, allowing the internal magnetization state of the antiferromagnet to be transferred to and read out through the ferromagnet's magnetization, which can be externally detected while the antiferromagnet maintains its spin-cancelled stable configuration.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution reduces the difference in energy required for transitioning between magnetization states, stabilizing the switching operation and enabling efficient data writing by balancing the energy applied through exchange coupling and Zeeman energy.

Implementation Method 1

a magnetization control layer containing a magnetoelectric material exhibiting a magnetoelectric effect

Methodology Applied

Scientific EffectMagnetoelectric effect:

Implementation Method 2

a magnetic coupling layer that is magnetically coupled to a magnetization of a first surface of the magnetization control layer through exchange coupling

Methodology Applied

Scientific EffectExchange coupling:

Data Source

PatentUS11244781B2Magnetization control element, magnetic memory, and magnetic recording system

Publication Date: 2022.02.08 TDK CORP

AI summary

A magnetization control element according to an aspect of the invention includes a magnetization control layer containing a magnetoelectric material exhibiting a magnetoelectric effect, and a magnetic coupling layer that is magnetically coupled to a magnetization of a first surface of the magnetization control layer through exchange coupling and exhibits a magnetic state according to the magnetization of the first surface, wherein a magnetization having a component in a direction opposite to a direction of a magnetization of the magnetic coupling layer is imparted to the magnetization control layer.