Accession Number : AD0827768

Title :   MICROWAVE PROPERTIES OF PARTIALLY MAGNETIZED FERRITES.

Descriptive Note : Semi-annual technical rept. 5 Jul 67-5 Jan 68,

Corporate Author : RAYTHEON CO WALTHAM MA RESEARCH DIV

Personal Author(s) : Green, Jerome J. ; Patton, Carl A. ; Sandy, Frank

Report Date : JAN 1968

Pagination or Media Count : 54

Abstract : Measurements of mu' and kappa' as a function of gamma 4 pi M sub s/omega and gamma 4 pi M/omega have been made on two common, commercially available, polycrystalline ferrites, G-113, a yttrium iron garnet, and TT1-390, a magnesium manganese spinel. The corresponding absorption components of the tensor permeability have also been measured on G-113 at room temperature. mu double prime-kappa double prime shows a peak at negative fields. A system to measure magnetic loss in the demagnetized state on very low loss materials having mu double prime in the 10 to the -4th power or 10 to the -5th power region has been built and several materials have been measured. Measurements of the spin wave instability threshold, hcrit, have been made on partially magnetized thin disks. An attempt to understand the dependence of hcrit as a function of orientation of the disks, the rf magnetic field, and the dc magnetization in terms of the domain structure and the behavior of hcrit in magnetically saturated disks is being made. (Author)

Descriptors :   (*FERRITES, MAGNETIC PROPERTIES), TENSOR ANALYSIS, STABILITY, MICROWAVE FREQUENCY, GARNET, IRON COMPOUNDS, YTTRIUM COMPOUNDS, MAGNESIUM COMPOUNDS, MANGANESE COMPOUNDS, HYSTERESIS, PERMEABILITY(MAGNETIC), DISKS, PHASE SHIFT CIRCUITS.

Subject Categories : Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE