Investigation of Magnetostatic Surface Waves for Anisotropic Effects

摘要

A unique test apparatus was designed in order to investigate the effect of launching magnetostatic surface waves at different angles on a yttrium-iron-garnet (YIG) single crystal film. Many characteristics of the Magnetostatic waves were measured, including amplitude, time delay, and beam steering. There was slight dependence of these characteristics on the launch angle. A second, more sensitive technique using the YIG films as delay lines in an oscillating circuit, was found to verify the influence of magnetocrystalline anisotropy on the magnetostatic surface wave. A calculated shift in frequency of the oscillator was found to be in agreement with previous calculations and measurements of anisotropic constants. In addition to these findings, an investigation of the influence of a metallization spaced closely to the propagation path was performed due to its influence on the above measurements. This metallization altered the velocity of the magnetostatic wave and demonstrated, for the first time, the refraction of a magnetostatic wave. This technique may prove useful for instantaneous frequency selection in electronic countermeasure equipment. Keywords: Magnetostatic; anisotropy; magnetostatic surface waves; refraction; beam steering; magnetostatic delay line oscillator. (Author)