Magnetic Sensors and Magnetometers

✍ Scribed by Pavel Ripka (editor)

• Publisher: Artech House
• Tongue: English
• Leaves: 417
• Category: Library

✦ Synopsis

The textbook on magnetic sensors and magnetometers has been substantially upgraded for this edition, concentrating more on the sensor-related effects such as shape anisotropy and magnetostriction and on electric current sensors, which are in much more demand since the advent of smart grids, renewable energy resources, and electric vehicles. It also incorporates milestones in magnetic sensor technology during the past two decades. Among the topics are induction sensors, fluxgate sensors, resonance magnetometers, magneto-optical sensors and other principles, testing and calibrating instruments, and magnetic sensors for non-magnetic variables. Annotation ©2021 Ringgold, Inc., Portland, OR (protoview.com)

✦ Table of Contents

Magnetic Sensorsand Magnetometers Second Edition
Contents
Preface to the First Edition
References
Preface to the Second Edition
Acknowledgments
Chapter
1 Basics
1.1 Magnetic Units and Basic Rules
1.1.1 Basic Laws
1.1.2 Magnetic Field and Matter
1.1.3 Magnetic Circuits
1.2 Magnetic States of Matter
1.2.1 Diamagnetism and Superconductivity
1.2.2 Paramagnetism
1.2.3 Ferromagnetism, Antiferromagnetism, and Ferrimagnetism
1.2.4 Superparamagnetism
1.3 Magnetic Anisotropy
1.3.1 Magnetocrystalline Anisotropy
1.3.2 Shape Anisotropy and Demagnetization
1.3.3 Induced Anisotropy
1.3.4 Anisotropy in Magnetic Wires
1.4 Magnetostriction
1.5 Domain Structure
1.6 Magnetization Process
1.6.1 Magnetization Curve
1.7 Magnetic Materials
1.7.1 Soft Magnetic Materials
1.7.2 Hard Magnetic Materials
1.8 Sensor Specifications
1.8.1 Full-Scale Range, Linearity, Hysteresis, and Temperature Coefficient of Sensitivity
1.8.2 Offset, Offset Temperature Coefficient, and Long-Term Stability
1.8.3 Perming
1.8.4 Noise
1.8.5 Resistance Against Environment (Temperature, Humidity, and Vibrations)
1.8.6 Resistance Against Perpendicular Field and Field Gradient
1.8.7 Bandwidth
1.8.8 Other (Power, Radiation Immunity, and Cost)
References
Chapter 2
Induction Sensors
2.1 Air Coils
2.1.1 Voltage Sensitivity at Low Frequencies
2.1.2 Thermal Noise
2.1.3 The Influence of the Parasitic Capacitances
2.1.4 Current-Output (Short-Circuited Mode)
2.2 Search Coils with a Ferromagnetic Core
2.2.1 Voltage Output Sensitivity
2.2.2 Thermal Noise of the Cored Induction Sensor (Voltage Output)
2.2.3 The Equivalent Circuit for Cored Coils
2.2.4 Cored Coils with Current Output
2.3 Noise Matching to an Amplifier
2.4 Design Examples
2.5 Other Measuring Coils
2.5.1 Rotating Coil Magnetometers
2.5.2 Moving Coils: Extraction Method
2.5.3 Vibrating Coils
2.5.4 Coils for Measurement of H
2.5.5 The Rogowski-Chattock Potentiometer
References
Chapter 3
Fluxgate Sensors
3.1 Orthogonal-Type Fluxgates
3.2 Core Shapes of Parallel-Type Fluxgates
3.2.1 Single-Rod Sensors
3.2.2 Double-Rod Sensors
3.2.3 Ring-Core Sensors
3.2.4 Racetrack Sensors
3.3 Theory of Fluxgate Operation
3.3.1 The Effect of Demagnetization
3.4 Core Materials
3.5 Principles of Fluxgate Magnetometers
3.5.1 Second-Harmonic Analog Magnetometer
3.5.2 Digital Magnetometers
3.5.3 Nonselective Detection Methods
3.5.4 Auto-Oscillation Magnetometers
3.6 Excitation
3.7 Tuning the Output Voltage
3.8 Current-Output (or Short-Circuited) Fluxgate
3.8.1 Broadband Current-Output
3.8.2 Tuning the Short-Circuited Fluxgate
3.9 Noise and Offset Stability
3.9.1 Zero Offset
3.9.2 Offset from the Magnetometer Electronics
3.9.3 Other Magnetometer Offset Sources
3.10 Crossfield Effect
3.11 Designs of Fluxgate Magnetometers
3.11.1 Portable and Low-Power Instruments
3.11.2 Station Magnetometers
3.12 Miniature Fluxgates
3.12.1 Miniature Wire-Wound Sensors
3.12.2 Devices with Flat Coil (CMOS or Other Technologies)
3.12.3 PCB-Based Sensors with Solenoid Coils Made of Tracks and Vias
3.12.4 Sensors with Microfabricated Solenoids
3.13 AC Fluxgates
3.14 Multi-Axis Magnetometers
3.14.1 Three-Axial Compensation Systems
3.14.2 Individually Compensated Sensors
3.15 Fluxgate Gradiometers
References
Chapter 4
Ferromagnetic Magnetoresistive Sensors
4.1 AMR Sensors
4.1.1 Magnetoresistance and Planar Hall Effect
4.1.2 Magnetoresistive Films
4.1.3 Linearization and Stabilization
4.1.4 Sensor Layout
4.1.5 Crossfield Sensitivity of the AMR Sensor
4.1.6 AMR Magnetometers
4.2 GMR and TMR (SDT) Sensors
4.2.1 GMR Effect Basics
4.2.2 Tunnel Magnetoresistance (Spin-Dependent Tunneling)
4.2.3 GMR/TMR Sensor Design
4.2.4 Magnetoresistance Sensor Applications
4.3 Operating Parameters of Magnetoresistive Sensors
4.3.1 Noise
4.3.2 Field Range and Linearity
4.3.3 Offset, Offset Drift, and Hysteresis
References
Chapter 5 Hall-Effect Magnetic Sensors
5.1 Basics of the Hall Effect and Hall Devices
5.1.1 The Hall Effect
5.1.2 Structure and Geometry of a Hall Device
5.1.3 Main Characteristics of Hall Magnetic Field Sensors
5.1.4 Other Problems
5.2 High Electron Mobility Thin-Film Hall Elements
5.2.1 InSb Hall Elements
5.2.2 InAs Thin-Film Hall Elements by MBE
5.2.3 Deep Quantum Wells (DQW) and Application to Hall Elements
5.2.4 GaAs Hall Elements
5.3 Integrated Hall Sensors
5.3.1 Historical Perspective
5.3.2 CMOS Hall Elements
5.3.3 Hall Offsets
5.3.4 Excitation
5.3.5 Amplification
5.3.6 Geometry Considerations
5.3.7 Vertical Hall Elements
5.3.8 Packaging for Integrated Hall Sensors
5.3.9 Applications and Trends
5.4 Nonplate-Like Hall Magnetic Sensors
5.4.1 The Vertical Hall Device
5.4.2 Two-Axis Vertical Hall Device
5.4.3 Three-Axis Hall Devices
5.5 Hall Devices with Integrated Magnetic Concentrators (IMCs)
5.5.1 Rotary Sensor with IMC
5.5.2 3-Axis Sensor with IMC
5.5.3 Integrated Current Sensor [55]
5.5.4 Stray-Field Robust Gradiometric Sensors [56]
5.5.5 IMC Technology
References
Chapter 6
Resonance Magnetometers
6.1 Introduction to Magnetic Resonance
6.1.1 Historical Overview
6.1.2 Absolute Reproducibility of Magnetic Field Measurements
6.2 Proton Precession Magnetometers
6.2.1 The Mechanical Gyroscope
6.2.2 The Classic Proton-Free Precession Magnetometer
6.2.3 Overhauser Effect Proton Magnetometers
6.3 Optically Pumped Magnetometers
6.3.1 Alkali Metal Vapor Magnetometers
6.3.2 The Metastable He4 Magnetometer
References
Chapter 7
SQUID
7.1 Introduction
7.1.1 Superconductivity
7.1.2 Meissner Effect
7.1.3 Flux Quantization
7.1.4 The Josephson Effect
7.1.5 SQUIDs
7.2 SQUID Sensors
7.2.1 Materials
7.3 SQUID Operation
7.3.1 The RF SQUID
7.3.2 The DC SQUID
7.3.3 SQIFs
7.3.4 Fractional-Turn SQUIDs
7.3.5 The Bi-SQUID
7.4 Noise and Sensitivity
7.4.1 White Noise
7.4.2 Temperature Dependence
7.4.3 Field Dependence
7.4.4 1/f Noise
7.5 Control Electronics
7.6 Limitations on SQUID Technology
7.7 Input Circuits
7.7.1 Packaging
7.7.2 The SQUID as a Black Box
7.7.3 Sensitivity
7.7.4 Detection Coils
7.7.5 Gradiometers
7.7.6 Electronic Noise Cancellation
7.8 Refrigeration
7.8.1 Dewars
7.8.2 Closed Cycle Refrigeration
7.9 Environmental Noise (Noise Reduction)
7.9.1 Gradiometers for Noise Reduction
7.9.2 Magnetic Shielding
7.10 Applications
7.10.1 Laboratory Applications
7.10.2 Cryogenic Current Comparators (CCC)
7.10.3 Geophysical Applications
7.10.4 Nondestructive Test and Evaluation
7.10.5 Medical Applications of SQUIDs
References
Chapter 8
Magneto-Optical Sensors and Other Principles
8.1 Magneto-Optical Sensors
8.1.1 Faraday Effect and Optical Sensors of the Magnetic Field
8.1.2 Magneto-Optical Kerr Effect and Observation of Domains
8.2 Magnetoimpedance and Magnetoinductance
8.2.1 Principle
8.2.2 Materials
8.2.3 Sensors
8.3 Magnetoelastic Field Sensors
8.3.1 Fiber-Optic Magnetostriction Field Sensors
8.3.2 Magnetostrictive-Piezoelectric (Magnetoelectric) Sensors
8.3.3 Shear-Wave Magnetometers
8.4 Lorentz Force Magnetometers
8.5 Biological Sensors
8.5.1 Magnetotactic Bacteria
8.5.2 Magnetic Orientation in Birds
References
Chapter 9
Applications of Magnetic Field Sensors and Magnetometers
9.1 Biomagnetic Measurements
9.2 Navigation
9.3 Military and Security
9.3.1 Unexploded Ordnance (UXO)
9.3.2 Target Detection and Tracking
9.3.3 Antitheft Systems
9.4 Automotive
9.5 Nondestructive Testing
9.6 Magnetic Marking and Labeling
9.7 Geomagnetic Measurements: Mineral Prospecting, Object Location, and Variation Stations
9.8 Space Research
9.8.1 Deep-Space and Planetary Magnetometry
9.8.2 Space Magnetic Instrumentation
9.8.3 Measurement of Magnetic Fields Onboard Spacecraft
References
Chapter 10
Testing and Calibration Instruments
10.1 Calibration Coils
10.1.1 Coils as Sources of the Magnetic Moment
10.2 Field Compensation Systems
10.3 Magnetic Shielding
10.3.1 Magnetic Shielding Theory
10.3.2 Transverse Magnetic Shielding
10.3.3 Axial Magnetic Shielding
10.3.4 Flux Distribution
10.3.5 Annealing
10.3.6 Demagnetizing
10.3.7 Enhancement of Magnetic Shielding by Magnetic Shaking
10.3.8 Magnetic Shielded Rooms
10.4 Calibration of 3-Axial Magnetometers
10.4.1 Vectoral Calibration of 3-Axial Magnetometers
10.4.2 Scalar Calibration of 3-Axial Magnetometers
References
Chapter 11
Magnetic Sensors for Nonmagnetic Variables
11.1 Position Sensors
11.1.1 Sensors with a Permanent Magnet
11.1.2 Eddy-Current Sensors
11.1.3 Linear Transformer Sensors
11.1.4 Rotation Transformer Sensors
11.1.5 Magnetostrictive Position Sensors
11.1.6 Wiegand Sensors
11.1.7 Magnetic Trackers
11.2 Proximity and Rotation Detectors
11.3 Force and Pressure
11.4 Torque Sensors
11.5 Magnetic Flowmeters
11.6 Electric Current Sensors
11.6.1 Magneto-Optical Current Sensors
11.6.2 Current Transformers
11.6.3 Fluxgate Current Sensors
11.6.4 Rogowski Coils
11.6.5 Sensors with a Gapped Core
11.6.6 Coreless Current Sensors
11.6.7 Current Clamps
11.6.8 Magnetometric Measurement of Hidden Currents
References
Acronyms and Abbreviations
About the Editor
List of Contributors
Index