Accession Number : AD0276084

Title :   RESEARCH AND DEVELOPMENT OF YTTRIUM IRON GARNET SINGLE CRYSTALS

Corporate Author : TEXAS INSTRUMENTS INC DALLAS

Report Date : 15 MAR 1962

Pagination or Media Count : 1

Abstract : Yttrium iron garnet (YIG) single crystals 1/4 to 3/8 in. diameter with a dielectric constant of about 10 and 0.002 dissipation factor have been produced by the floating zone technique. Ferrimagnetic resonance line-widths of less than 2 oersteds were obtained from polished test spheres. Thermal cracking remains a major problem in growing YIG crystals by the floating zone method. A calcia-stabilized ZrO2 susceptor was placed on a MoSi2 auxiliary susceptor to decrease the thermal gradient just below the molten zone; however, the resultant decrease was insufficient to eliminate thermal cracks. Various arrangements and combinations of work coil, susceptor, auxillary susceptor, and auxiliary resistance heater were used to give a temperature profile along the axis of the zoned YIG that would prevent formation of thermal cracks. Although the amount of cracking was reduced, it was not completely eliminated. Analytical results given compare the impurity concentration of YIG crystals grown in the old and the new floating zone apparatus. Representative values of ferrimagnetic resonance line-width obtained from polished spheres of single crystal YIG are presented. (Author)

Descriptors :   *FERROMAGNETIC MATERIALS, *GARNET, *SINGLE CRYSTALS, DIELECTRIC PROPERTIES, GROWTH(PHYSIOLOGY), IRON COMPOUNDS, MAGNETIC PROPERTIES, OXIDES, YTTRIUM COMPOUNDS

Distribution Statement : APPROVED FOR PUBLIC RELEASE