Solid-State Devices Other than Semiconductors

The solid-state properties of matter are of interest not only to the research scientist but also to the engineer who has translated the findings of basic research into endeavors of great technological significance. The research in ferromagnetism has led to the magnetic amplifier, which for certain applications is superior to amplifiers using vacuum tubes and to the development of new materials such as ferrites, which are now finding use at radio frequencies in pulse transformers, radio frequency inductors, antenna rods, magnetic core delay lines, computer elements, and magnetic recording media. Ferrites and antiferromagnetic materials are now also widely used at microwave frequencies and millimeter wavelengths as nonreciprocal phase shifters, load isolators, filters, ferrite switches, ferrod radiators, modulators and power limiters. Such phenomena as piezoelectricity, ferroelectricity and magnetostriction have resulted in the use of ultrasonic waves for the study of phononelectron and phonon-spin interactions as well for such practical devices as the detection of imperfections and faults in solids, electromechanical transducers, resonators, filters, delay lines, computer memories, ultrasonic soldering, cleaning, drilling and cutting, and strain and acceleration gauges. Dielectric materials have found applications as prisms, polarizers, restrahlen plates and more recently in dielectric wave guides and fiber optics.