TRANSMISSION LINE MODELS OF MAGNON-PHONON MODES IN FERRITES. PART II. COUPLED MODES.
Physical sciences research papers no. 327,
AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS
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In AD-641 638 uncoupled transmission line models for circularly-polarized shear waves and magnons in ferrites are described. Voltage and current variables are defined in terms of magnetic and mechanical variables and line elements are related to magnon-phonon parameters. Three models of coupled modes are now developed. The models are analytically equivalent but they differ in their physical interpretation. One model uses controlled sources as the coupling elements, and another uses a distributed transformer. Coupling in the final model is accounted for by line element modifications in the presence of mutual coupling. Boundary conditions for the distributed transformer coupling model are given. They include capacitive terminations on the magnetic line, a lumped transformer between magnetic and acoustic lines, and the loading of the combined system with a third acoustic line. These boundary conditions account for arbitrary acoustic loading of the magneto-acoustic media by a phonon supporting substrate and a range of boundary conditions between pinned and unpinned spin for the magnetic system. Distributed and nondistributed externally controlled sources may be placed anywhere in the coupled system. A Poyntings-type theorem for each model and expressions for group velocity, magneto-elastic resonant frequencies, and Qs are derived. A brief summary and conclusion which discusses various aspects of the coupled transmission line models is given. Author
- Electricity and Magnetism
- Solid State Physics