Giant Magnetoimpedance: Concepts and Recent Progress Introduction

Giant Magnetoimpedance: Concepts and Recent Progress

Introduction

Presentation Outline

• Introduction

• Giant Magnetoimpedance

• Discovery
• Basic Concepts

• Experimental Results and Theories

• Quasistatic Models (Low Frequency Regime)
• Eddy Current Damping+Magnetic Resonance (Moderate Frequency Regime)
• Dynamic Effects, FMR features (High Frequency Regime)
• Examples on Amorphous Ribbons, Wires and Microwires; Nanocrystalline Materials; Crystalline Materials

• GMI as a Tool to Investigate Magnetic Properties

• Applications of GMI

• Conclusions

Acknowledgments

• C. Gómez-Polo, Universidad Publica de Navarra, Pamplona, Spain.

• M. Vázquez, CSIC, Madrid, Spain.

• L. Kraus, Czech Academy of Sciences, Prag, Czech Republic.

• J. P. Sinnecker, Universidade Federal do Rio de Janeiro, UFRJ, Brazil.

• M. L. Sartorelli, Universidade Federal de Santa Catarina, Florianópolis, Brazil.

• Fábio C.S. Silva, J. Schoenmaker, former students at LMBT, UNICAMP.

• Financial support:

• M-4 Conference, FAPESP and CNPq

Collaborations

• M. Vázquez, A. Hernando, J. Velázquez, P. Marín, D.X. Chen, Instituto de Magnetismo Aplicado, Madrid, Spain.

• R. Valenzuela, Universidad Autonoma de Mexico, Mexico.

• M.L. Sánchez, B. Hernando, M. Tejedor, Universidad de Oviedo, Oviedo, Spain.

• H. Chiriac, Institute of Technical Physics, Iasi, Romania.

• R. Grössinger, R. Sato Turtelli, H. Sassik, TU Wien, Vienna, Austria.

• J. Gutierrez, J.M. Barandiarán, UPV, Bilbao, Spain.

• H. Sirkin, B. Arcondo, J. Moya, V. Cremaschi, Lab. Sólidos Amorfos, Universidad de Buenos Aires, Argentina.

• F.G. Gandra, C. Rettori, IFGW, UNICAMP, Brazil.

GMI Discovery

• Huge and sensitive changes of the electrical impedance of soft magnetic materials upon the application of an external magnetic field.

• Magnetic Sensors (Amorphous Ribbons)

• 1991: Makhotkin et al.

• Amorphous Ribbons

• 1993-1994: Machado, Martins and Rezende

• Amorphous Wires

• 1994: Panina and Mohri; Beach and Berkowitz; Velázquez, Vázquez, Chen and Hernando.

• Nanocrystalline Materials

• 1995: Knobel, Sánchez, Gómez-Polo, Marín, Vázquez and Hernando.

• Crystalline Fe-Si

• 1996: Carrara and Sommer.

GMI: Evolution of Published Papers

GMI: Amorphous Wire

Giant Magneto-Impedance (GMI)

• Origin: skin effect

• Impedance Z depends on the magnetic penetration depth m
• Dependence on magnetic circular permeability 

Origin of GMI

THEORETICAL MODELS

• Low frequency regime (1-10 kHz) :

• Quasistatic models (Machado and Rezende 1996, Atkinson and Squire 1997, 1998)

• Moderate frequency regime (10 kHz – few MHz):

• Eddy currents damping + magnetic resonance models (Panina and Mohri 1994, 1995)

• High frequency regime (dozen MHz - GHz):

• Dynamic effects, FMR features (Yelon et al 1996, Kraus 1998)

Double-Peak Behavior

Low Frequency Regime: Quasistatic Models

Simulation

Calculation of the current distribution

Current distribution of Simple Magnetic Wires (Mumetal)

Electroplated wires

Finite Element Method

Current distribution of Electrodeposited Wires

• Frequency dependence

Field distribution of Electrodeposited Wires

• Field Distribution

Current distribution of Electrodeposited Wires

Moderate Frequency Regime

High Frequency Regime

High Frequency Regime

High Frequency Regime

High Frequency Regime

High Frequency Regime

Experimental Setup

Experimental Setup

Experimental Setup

• Current control

• Use of resistors
• Limited to rather low frequencies
• Inductive behavior of resistors at high frequencies

Experimental Setup

Experimental Setup

Recent Progress

• It is remarkably difficult to make a complete review of all published experimental data on GMI, because a huge amount of works have been published in the last few years.

• Conventional measurements are explored to test the validity of some theoretical models, while different geometries and techniques are employed to gather new insights about some unclear points.

• Furthermore, a great quantity of investigations deal with different kinds of materials subjected to a broad variety of annealings, which are performed in order to induce specific magnetic anisotropies, modifying the GMI response.

• Few selected examples will be shown in this talk.

Results: GMI vs. S

Nanocrystalline Materials

• Combined role of resistivity, permeability and induced anisotropies.

• Drastic reduction of Aftereffect (see below). 

• Bad mechanical properties. 

Glass Covered Microwires

Fe73.5Cu1Nb3Si13.5B9 amorphous films at microwave frequencies

Asymmetrical GMI

Asymmetrical GMI

Asymmetrical GMI

Granular Materials

Other Systems

GMI as a Research Tool

GMI as a Research Tool

Effect of Stress on GMI

Evaluation of s through GMI measurements

Angular Dependence of GMI

Angular Dependence of GMI

Measurements of Ferromagnetic Resonance and Antiresonance

Modelization through Fourier Harmonic Contribution

Modelization through Fourier Harmonic Contribution

Modelization through Fourier Harmonic Contribution

Applications

• Many applications of GMI have been proposed so far. By choosing an appropriate material, and performing specific thermal treatments it is possible to tailor special impedance responses, depending on the desired application.

• The high sensitivity of GMI to external dc field, drive current frequency and tensile stress makes soft magnetic materials specially convenient for sensor applications.

• Therefore, from the application point of view, many uses of GMI materials have been idealized and developed, with very interesting perspectives.

GMI: Applications

GMI: Applications

GMI: Applications

GMI: Applications

GMI: Applications

GMI: Applications

• The Japan Science and Technology Corporation (JST) selected the following theme as new commission-basis development task and announced the enterprises to be commissioned with their development:

• Automobile-loaded magnetic impedance sensors

• "Automobile-loaded magnetic impedance sensors" given high environment resistance by strengthening the junction between the sensor head and electronic parts and compensating for the temperature stability of the high-frequency circuit is a research result of Professor Kaneo Mohri of Dept. of Electrical Engineering, Graduate School of Engineering , Nagoya University. Its development for practical use is to be commissioned to Aichi Steel Corporation (based in Tokai City, Aichi Prefecture) with the development period of 4 years and development expenditures of 600 million yen.
• Since a magnetic sensor is not affected by splashes of water and mud, dust and exhaust gas in its dective properties, it is used for various measurement applications including the measurement of rotation number of an axle and loaded on automobiles. However, the conventional-type magnetic sensor requires to compensate for lack of sensitivity in the precise mechanism for mechanical positioning.
• The magnetic impedance effects were discovered by the above-mentioned researcher, and the application development of the sensor which uses the effects has been advanced as the smallsized and low electricity-consumption sensor having the sensitivity 100 times or more as high as that of the conventional type. However, the junction between amorphous wire the sensor head and electric terminal have destructible by mechanical oscillation. And the high-frequency circuit have been unstable to drastic temperature fluctuations, and it has been unable to utilize its properties sufficiently under such a harsh environment as being loaded on automobiles.

GMI: Applications

GMI: Applications

GMI Applications

GMI: Applications

GMI: Applications

GMI: Applications

• Alliance with Macnica to Expand Market in Info-communications to Mass-produce Micro-mini, High Sensitive MI Sensor Modules for Mobile Phones

• A long-awaited Magnetic Checker: Dental Magnet Tester Released (Applied for trademark )

GMI: Applications

GMI: Applications

GMI Sensors

GMI Sensors

GMI: Applications

GMI Sensors: PIG

GMI Sensors

GMI Sensors

GMI Stress Sensor

GMI Stress Sensor

Non-linear response

Impedance Relaxation

Hysteretic GMI

Conclusions

• Owing to the rapid development of theories and applications, supported by systematic experimental investigations, it is possible to predict a fruitful future to the GMI effect.

• Theories and Basic Research:

• Although each day the GMI phenomenon is better uderstood, there are still many points that remain to be clarified. Systematic experimental studies, supported by theoretical models, are being presently developed, in order to understand all basic aspects of this interesting effect.

• GMI as a tool:

• Once the theories become more and more acurate, it will be possible to use the GMI effect as an additional tool to study soft magnetic materials, including the distribution of quenched-in and induced anisotropies, magnetoelastic behaviour, ferromagnetic resonance and anti-resonance, domain structure.

• Applications:

• There are already working prototipes and devices in the market that make use of GMI, with several advantages when compared with other available sensors. The progress on models and experimental data will lead to improved materials from the applications viewpoint, mainly highly-sensitive magnetic sensors.

Conclusions

The End