Solid State Physics

Chapter 6

Dielectric Properties

6.1 INTRODUCTION

Dielectrics represent a class of materials that, although insulators, exhibit a number of effects when placed in an electric field. A good example is their effect on capacitors. A capacitor in simple case is a pair of parallel plates, the space between which has been filled with a dielectric material and the two plates are attached to a voltage source. A capacitor has a capacitance C₀ when the space between its two conductors is vacuum, and when this space is filled with a dielectric, the capacitance increases to a value C_m (say) and the ratio, C_m/C₀ = ɛ, is known as the permittivity of the dielectric or the dielectric constant.

To understand the property of dielectrics, it is better to consider ...