Tunnel Magnetoresistance Device with Gradient Antiferromagnetic Layer

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Solution Overview

Problem

Tunnel magnetoresistance effect devices face challenges in maintaining stability and strong-magnetic field resistance in high-temperature environments, limiting their performance in severe conditions.

Innovation Solution

A tunnel magnetoresistance effect device with a structure featuring a ferromagnetic layer and an antiferromagnetic layer, where the antiferromagnetic layer includes an X(Cr—Mn) layer with varying Mn content regions, forming an exchange coupling film that enhances the exchange-coupled magnetic field and maintains stability even at high temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional TMR device structure is used, then the device achieves basic magnetoresistance function, but the device fails to maintain stability and strong-magnetic field resistance in high-temperature environments

Engineering Contradiction:

Improvestability in high-temperature environmentVSAvoidhigh-temperature environment

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent modifies the composition parameters of the antiferromagnetic layer by incorporating specific elements (Ru, Rh, Ir, Os, Pt, Pd, Au, or Cu) in controlled concentrations (1-50 at%). This compositional parameter change enhances the exchange coupling strength and maintains device stability at high temperatures without sacrificing the TMR effect functionality

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite antiferromagnetic layer structure combining transition metal elements (Cr, Mn, Fe, Co, Ni) with platinum group elements or Cu. This composite material approach leverages the complementary properties of each element to achieve both strong exchange coupling and high-temperature stability, resolving the contradiction between basic function and environmental reliability

Inventive Principle:

Principle #40Composite materials

2Reliability

If a conventional antiferromagnetic layer is used, then the device structure is simple, but the device lacks strong-magnetic field resistance in high-temperature environments

Engineering Contradiction:

Improvestrong-magnetic field resistanceVSAvoidantiferromagnetic layer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating specific regions within the antiferromagnetic layer with different elemental compositions. The gradient composition (with platinum group elements or Cu distributed at specific positions) provides localized enhancement of exchange coupling strength where needed, achieving strong-magnetic field resistance without uniformly complicating the entire layer structure

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent carefully controls the concentration parameters of added elements (1-50 at%) to optimize the balance between exchange coupling strength and structural simplicity. This parameter optimization ensures that the enhanced magnetic field resistance is achieved with minimal increase in structural complexity

Inventive Principle:

Principle #35Parameter changes

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 device exhibits excellent strong-magnetic field resistance and stability in high-temperature environments, enabling reliable operation in severe conditions and suitable for various applications.

Implementation Method 1

The ferromagnetic layer and an antiferromagnetic layer laminated on the ferromagnetic layer constitute an exchange coupling film

Methodology Applied

Scientific EffectExchange coupling: Magnetism

Implementation Method 2

A tunnel magnetoresistance effect (TMR) device having a structure in which a fixed magnetic layer and a free magnetic layer are laminated through an insulating barrier layer has a higher magnetoresistance ratio (MR ratio)

Methodology Applied

Scientific EffectTunnel magnetoresistance effect: Magnetoresistance

Data Source

PatentUS11476413B2Tunnel magnetoresistance effect device and magnetic device using same

Publication Date: 2022.10.18 ALPS ALPINE CO LTD

AI summary

A tunnel magnetoresistance effect (TMR) device includes an exchange coupling film having a first ferromagnetic layer, which is at least a portion of a fixed magnetic layer, and an antiferromagnetic layer laminated on the first ferromagnetic layer. The ferromagnetic layer includes an X(Cr—Mn) layer containing one or two or more elements X selected from the group consisting of the platinum group elements and Ni, and also containing Mn and Cr. The X(Cr—Mn) layer has a first region relatively near the first ferromagnetic layer, and a second region relatively far away from the first ferromagnetic layer, and the content of Mn in the first region is higher than that in the second region.