Accession Number : AD0603934

Title :   THE CONTRIBUTION OF THE TWO-MAGNON PROCESS TO MAGNETOSTATIC MODE RELAXATION,

Corporate Author : HARRY DIAMOND LABS WASHINGTON D C

Personal Author(s) : Nemarich,Joseph

Report Date : 10 AUG 1964

Pagination or Media Count : 33

Abstract : The linewidths of the magnetostatic modes have been measured at x-band with the static magnetic field along the (111) direction in several highly polished spheres of single-crystal pure yttrium iron garnet (YIG). The large variations of the magetostatic mode linewidths previously found in larger linewidth spheres were not observed in highly polished YIG spheres. However, there is a residual variation of mode linewidths at both 300K and 4.2K, the variations being somewhat larger at 4.2K. It was found that the essential features of the variation of mode linewidths in a highly polished YIG sphere can be explained by the surface pit-scattering theory of Sparks, Loudon, and Kittel when the linewidth predicted by this theory is multiplied by an enhancement factor F sub nmr to include the effect of the spatial variation of magnetization intensity for the individual magnetostatic modes. The observed spectrum of magnetostatic modes in a YIG sphere at 4.2K are presented and compared with the theoretical spectrum for modes up to order n = 6. The agreement between the calculated and observed spectrum is good if propagation effects are taken into account.

Descriptors :   (*MAGNETIC RESONANCE, MAGNETIC MATERIALS), (*MAGNETIC MATERIALS, SINGLE CRYSTALS), YTTRIUM, IRON, GARNET, SPHERES, LINE SPECTRA, X BAND, MAGNETIC FIELDS, MEASUREMENT, SURFACE PROPERTIES, SCATTERING, MATHEMATICAL ANALYSIS, IMPURITIES, RARE EARTH ELEMENTS, RELAXATION TIME, DIELECTRICS

Distribution Statement : APPROVED FOR PUBLIC RELEASE