In this volume of the highly esteemed Physics of Thin Films serial, focused coverage is given to new trends in solid state devices. Four chapters combine to provide comprehensive discussions of magnetostatic wave phenomena in epitaxial magnetic oxide films and their applications in microwave signal processing devices: Thin-film rare earth transition metal alloys for magnetooptic recording. Two new classes of quantum well structures that have been used for infrared detectors and ultrafast resonant tunneling devices. Recent applications of Fourier transform spectroscopy for the analysis of inorganic thin solid films. This book provides a focused treatment of recent developments in novel thin film solid state components, and specifically discusses magnetic, semiconducting, and optical phenomena.