Understanding Solids (The Science of Materials) || Insulating Solids

✍ Scribed by Tilley, Richard J. D.

• Publisher: John Wiley & Sons, Ltd
• Year: 2005
• Tongue: English
• Weight: 382 KB
• Category: Article
• ISBN: 0470852755
• DOI: 10.1002/0470020849.ch11

✦ Synopsis

How are the relative permittivity and refractive index of a transparent solid related? What is the relationship between ferroelectric and pyroelectric crystals? How can a ferroelectric solid be made from a polycrystalline aggregate?

Solids have traditionally been divided into three classes when the electrical properties are described. Those that conduct electricity well are called conductors. This group is typified by metals. Those solids that conduct poorly are called semiconductors. This group contains elements such as silicon and germanium, and large numbers of minerals such as the iron sulphide fool's gold, FeS 2 . Solids that do not conduct electricity are called insulators or dielectrics. Many oxides, such as magnesium oxide, MgO, and most polymers, such as polyethylene, are insulators.

This division is far too coarse to encompass the wide range of electrical properties that are now known. It is quite feasible to turn an insulating oxide into a very good 'metallic ' conductor, and