Magnetic Sensor Layer Structure for Uniform Impedance Sensing

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Solution Overview

Problem

Existing magnetic sensors exhibit variations in magnetic properties among plural sensitive portions or sensors due to differences in magnetic material layers deposited on a substrate, leading to inconsistent performance.

Innovation Solution

A magnetic sensor design incorporating a secondary soft magnetic material layer with higher saturation magnetization than the main soft magnetic material layer, along with magnetic domain suppression layers and a conductor layer, to stabilize magnetic domains and reduce variations in magnetic properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If soft magnetic material layers are deposited by magnetron sputtering to form the magnetic sensor body, then the magnetic sensor can be manufactured, but variations in magnetic properties occur among plural sensitive portions or sensors due to position differences on the substrate

Engineering Contradiction:

Improvemagnetic property uniformityVSAvoidperformance consistency

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

A secondary soft magnetic material layer with large saturation magnetization is deposited beforehand between the substrate and the main soft magnetic material layer. This preliminary layer pre-establishes a uniform magnetic environment across the substrate surface, compensating for position-dependent variations before the main sensitive layers are formed.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The saturation magnetization parameter is strategically varied between layers: the secondary soft magnetic material layer uses material with large saturation magnetization to dominate the magnetic properties near the substrate, while the main soft magnetic material layer uses material with smaller saturation magnetization for sensitivity. This parameter differentiation stabilizes the magnetic environment.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If multiple soft magnetic material layers are laminated to form sensitive portions, then the magnetic impedance effect can be enhanced, but differences in magnetic properties persist among sensors formed from the same substrate

Engineering Contradiction:

Improvemagnetic field sensing accuracyVSAvoidmagnetic property uniformity

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

Different saturation magnetization parameters are assigned to different layers: the secondary soft magnetic material layer (large saturation magnetization) stabilizes the magnetic environment, while the main soft magnetic material layer (smaller saturation magnetization) provides magnetic impedance sensitivity. This parameter stratification resolves the contradiction between enhancement and uniformity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The magnetic sensor structure combines multiple soft magnetic materials with different saturation magnetization characteristics into a composite layered system. This composite approach allows the secondary layer to provide magnetic stability while the main layer provides sensing functionality, achieving both enhanced performance and uniformity.

Inventive Principle:

Principle #40Composite materials

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 design stabilizes magnetic domains, reducing noise and enhancing sensitivity and consistency across multiple sensitive portions or sensors, thereby improving the magnetic impedance effect and measurement accuracy.

Implementation Method 1

the sensitive portion sensing a magnetic field by a magnetic impedance effect

Methodology Applied

Scientific EffectMagnetic impedance effect: Magnetoresistance

Implementation Method 2

the secondary soft magnetic material layer being composed of a soft magnetic material with large saturation magnetization compared to the soft magnetic material constituting the soft magnetic material layer

Methodology Applied

Scientific EffectMagnetic saturation: Magnetic Saturation

Implementation Method 3

the soft magnetic material layer sensing the magnetic field, and having uniaxial magnetic anisotropy in a direction intersecting the longitudinal direction

Methodology Applied

Scientific EffectMagnetic anisotropy: Anisotropy

Data Source

PatentUS12442873B2Magnetic sensor, method of manufacturing magnetic sensor, and sensitive element assembly

Publication Date: 2025.10.14 RESONAC CORP

AI summary

A magnetic sensor includes: a substrate; and a sensitive portion disposed on the substrate and having a longitudinal direction and a transverse direction. The sensitive portion senses a magnetic field by a magnetic impedance effect. The sensitive portion includes a soft magnetic material layer composed of a soft magnetic material having uniaxial magnetic anisotropy in a direction intersecting the longitudinal direction and sensing the magnetic field. The sensitive portion also includes a secondary soft magnetic material layer laminated between the substrate and the soft magnetic material layer. The secondary soft magnetic material layer is composed of a soft magnetic material with large saturation magnetization compared to the soft magnetic material constituting the soft magnetic material layer.