CHAPTER ONE

1.1            INTRODUCTION

Superconductivity is a fascinating and challenging field of physics. Scientists and Engineers throughout the world have been striving to develop it for many years. For nearly 75 years superconductivity has been a relatively obscure subject. Until recently, because of the cryogenic requirement of low temperature superconductors, superconductivity at the high school level was merely an interesting topic occasionally discussed in a Physics class. Today however, superconductivity is being applied to many diverse areas such as: medicine, theoretical and experimental science, the military, transportation, power production, electronics, as well as many other areas. With the discovery of high temperature superconductor which can operate at liquid nitrogen temperature (77k), superconductivity is now well known within the reach of high school student. Unique and exciting opportunities now exist today for our student to explore and experiment with this new and important technological field of Physics. Major advances in low-temperature refrigerator were made during the late 19th century. (Bedornz, J and Muller, K; 1986). 

1.2            PROBLEM STATEMENT

It is not practical to transmit electric energy if you need liquid helium temperatures. The cooling costs are prohibitive. The current state of the art are cables using thin films of BSCCO. They can operate at 77 K without problems. The current world record for such a cable in a vacuum tube is several kilometers but after some distance you need a small building along the cable to cool the liquid nitrogen inside the cable again.

There is a tremendous research effort to find superconductors with higher critical temperatures and currents but that is not so easy. The usage for practical applications is increasing but the progress is rather slow. In more exotic applications such a CERN or ITER you absolutely need superconducting cables, if it is only for space reasons: Well, Is it really possible to maintain such low temperatures required for super-conductors (taking High-temperature superconductivity into account) over large distances? What I say is - Even if we were able to pass current through superconductors, we need to constantly cool them for maintaining the zero resistance. Hence to cool, we need power. Then, superconductors wouldn't be necessary in this manner if they don't have an advantage..? Or, are there any new approaches to overcome these disadvantages?

1.3            OBJECTIVES OF THE STUDY

The primary objective of the study is to examine the energy gap in superconductors. Specific objectives of the study are:

1. To critically examine the various types and properties of super conductors

2. To examine energy gaps in low temperature super conductors.

3. To examine energy gaps in high temperature super conductors.

1.4            SIGNIFICANCE OF THE STUDY

The study will give more insights into the various ways superconductors can be utilised and improved. Superconducting materials are in the forefront of current research because of their very rich and fascinating properties and their applications in electrical and electronics technology and energy-saving materials. Superconductivity is a unique characteristic of certain materials that appears when the system temperature is dropped below a specific critical value and under such conditions the materials can carry electrical current with absolutely zero resistance.