Magnetoresistive Element With MnGa Storage Layer

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Solution Overview

Problem

Current magnetoresistive elements face challenges in achieving high-density, low-power nonvolatile memory integration due to high saturation magnetization and magnetic relaxation constants, as well as increased magnetic field leakage from smaller layers, which requires materials and methods to reduce interface roughness and diffusion.

Innovation Solution

A magnetoresistive element structure incorporating a MnGa alloy as the storage layer with a CsCl structured base layer, featuring a perpendicular magnetization type, low saturation magnetization, and low Gilbert damping constant, along with a tunnel barrier layer and interfacial magnetic layers to enhance spin polarizability and reduce diffusion, is developed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the size of magnetoresistive elements is reduced to increase density, then memory density is improved, but magnetic field leakage increases

Engineering Contradiction:

Improvememory densityVSAvoidmagnetic field leakage

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

A nonmagnetic layer is introduced as an intermediary between the storage layer and reference layer to shield magnetic field leakage. This mediator layer prevents direct magnetic interaction between adjacent magnetoresistive elements, thereby reducing harmful magnetic field leakage while maintaining high memory density

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent uses composite material structures including CoFeB alloy layers combined with specific insulating materials to create magnetoresistive elements with controlled magnetic properties. The composite structure allows optimization of both density and magnetic field confinement

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If the thickness of magnetic layers is reduced to lower saturation magnetization, then magnetization switching current is improved, but interface roughness and element diffusion increase

Engineering Contradiction:

Improvemagnetization switching currentVSAvoidinterface roughness

Core Design Contradiction:

Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent optimizes the thickness parameters of magnetic layers to achieve a balance between reducing saturation magnetization and maintaining acceptable interface quality. By carefully controlling layer thickness within specific ranges, the invention achieves low switching current while minimizing interface roughness and element diffusion effects

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The use of CoFeB alloy and other composite material systems provides better interface stability and reduced diffusion compared to conventional materials. The composite structure maintains low saturation magnetization while improving interface quality through material selection

Inventive Principle:

Principle #40Composite materials

3Reliability

If conventional magnetic materials are used in MTJ elements, then magnetoresistive effect is achieved, but write current density is high

Engineering Contradiction:

Improvemagnetoresistive effectVSAvoidwrite current density

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The patent changes the magnetic material parameters by using CoFeB alloy and optimizing magnetization orientation to achieve perpendicular magnetic anisotropy. This parameter change enables spin transfer torque switching with significantly reduced current density while maintaining strong magnetoresistive effects

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention utilizes phase transition concepts in the sense of switching between parallel and antiparallel magnetization states through spin transfer torque. The controlled phase transition of magnetization direction enables low-power writing operations

Inventive Principle:

Principle #36Phase transitions

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 efficient magnetization switching with reduced current density and improved magnetic anisotropy, achieving high-density, low-power magnetoresistive random access memory (MRAM) with enhanced magnetoresistance ratios and reduced magnetic field leakage.

Implementation Method 1

This MTJ element is known to have a tunneling magnetoresistive (TMR) effect

Methodology Applied

Scientific EffectTunneling magnetoresistive effect: Magnetoresistance

Implementation Method 2

where a technique called spin transfer torque switching is used to control magnetization with a spin-polarized current

Methodology Applied

Scientific EffectSpin transfer torque:

Data Source

PatentUS10256394B2Magnetoresistive element and magnetic memory

Publication Date: 2019.04.09 KIOXIA CORP

AI summary

A magnetoresistive element according to an embodiment includes: a first layer containing Al and at least one element of Ni or Co, the first layer having a CsCl structure; a first magnetic layer; a first nonmagnetic layer between the first layer and the first magnetic layer; and a second magnetic layer between the first layer and the first nonmagnetic layer, the second magnetic layer containing Mn and Ga.