Preface

This collection of seven chapters timely written by leading researchers and academics provide a comprehensive overview of the sensing fundamentals, principles, thermodynamic and phononic properties and recent developments in the applications of magnetic sensors in various fields such as local positioning, attitude control of micro-satellites, field sensors and biomedicine. An indispensable reference for budding researchers in this exciting field and application engineers from the industrial community, this compilation will bring the readers up to speed with the latest advances in the domain of magnetic sensing and their wide range of potential applications.

Chapter 1 provides an overview of the recent developments in the study of the thermodynamic and phononic properties of pure and doped perovskite manganites, outlining therein important information about their cohesive, thermal, elastic, phonon and vibrational properties. The author has also provided a comprehensive treatment of the background and theoretical basis associated with the study of specific physical properties in these materials. Using a recently developed Extended Rigid Ion Model, the author also outlined its usefulness in the providing a theoretical framework to explain the physical properties observed in these advanced materials. A separate work focusing on modeling of induction sensors is given in Chapter 2. Here, the authors highlight their method to model the induction sensor and how the information can be used to other types of sensors. An analytical model was summarized and methods to improve the sensing performation of the induction magnetometers are also discussed.

With the improvement in production techniques in microwires, orthogonal fluxgates as magnetic sensors are fast regaining prominence as the demand for small size sensors in modern applications are increasing at tremendous rates. Chapter 3 provides a comprehensive review of recent advancements in the area of orthogonal fluxgates. Methods of improving the various performance parameters such as sensitivity, linearity, noise of the sensor and physical structure of the orthogonal fluxgates are extensively presented in this chapter. Micro fluxgate sensors are given attention in Chapter 4 which outlines the use of microelectromechanical system (MEMS) manufacturing technology to fabricate this class of magnetic sensors. In addition, the chapter also described current research status in resonant sensors and Hall Sensors

### VIII Preface

focusing on devices fabricated by exploiting MEMS technologies and their possible applications.

The next chapters, with a emphasis on the applications and specification requirements of magnetic sensors when applied to attitude control in nano- and micro-stallite, local positioning system and biomedicine. In Chapter 5, the requirement for magnetometers in the nano- and micro-satellite missions, how these magnetometers are used in these small satellite missions are outlined. In view of the small size of these satellite systems, compensation of the magnetic moment experienced by these small-sized units needs careful attention which magneto sensors must be able to fulfilled when applied to such demanding applications. Chapter 6 presented a treatment of the requirements of local positioning system and the techniques and algorithm involved in inertial positioning. The integration of magnetic sensors and other sensors to the Kalman filter will improve the positioning accuracy of the system. Finally, the last chapter outlines a selection of magnetic-based sensors and actuators being researched for used in the field biomedicine. Specific requirements placed upon these sensing and actuating devices as encountered in this field are also highlighted.

> **Dr. Kevin Kuang**  Department of Civil and Environmental Engineering Faculty of Engineering National University of Singapore Singapore

VIII Preface

applications.

focusing on devices fabricated by exploiting MEMS technologies and their possible

The next chapters, with a emphasis on the applications and specification requirements of magnetic sensors when applied to attitude control in nano- and micro-stallite, local positioning system and biomedicine. In Chapter 5, the requirement for magnetometers in the nano- and micro-satellite missions, how these magnetometers are used in these small satellite missions are outlined. In view of the small size of these satellite systems, compensation of the magnetic moment experienced by these small-sized units needs careful attention which magneto sensors must be able to fulfilled when applied to such demanding applications. Chapter 6 presented a treatment of the requirements of local positioning system and the techniques and algorithm involved in inertial positioning. The integration of magnetic sensors and other sensors to the Kalman filter will improve the positioning accuracy of the system. Finally, the last chapter outlines a selection of magnetic-based sensors and actuators being researched for used in the field biomedicine. Specific requirements placed upon these sensing and actuating

**Dr. Kevin Kuang** 

Singapore

Faculty of Engineering

National University of Singapore

Department of Civil and Environmental Engineering

devices as encountered in this field are also highlighted.

**Part 1** 

**Theoretical Backgrounds and Principles** 
