Magnetic surface loading of Gunn oscillators and resulting new devices

Abstract

Theoretical results are described which concern the application of various materials to the longitudinal surfaces of Gunn-effect oscillators. As the analysis does not neglect the microwave magnetic field (i.e. no simple electrostatic wave potential was assumed), the effect of surface loading with magnetic materials of high effective permeability μ is studied. It is found that certain magnetic materials are suitable for domain suppression. It should be possible to switch a Gunn-effect device from the domain state to the subdomain state by using materials with a pronounced spin resonance at the relevant microwave frequencies. Logic gates are envisaged which are insensitive to feedback. A new electronically-controllable pulse function generator is proposed. Materials of high dielectric or magnetic properties effectively drain off all microwave power contained in the Gunn-effect instability. It will therefore be possible to detect the passage of a domain if low-absorption material is employed. Techniques are considered for matching space-charge waves inside the semiconductor to a stripline. Gunn-effect memory devices are studied which rely on surface loading. The use of spin-waves in ferrites employed as surface loads, is considered.