Accession Number : AD0474065

Title :   RESEARCH ON RELAXATION PROCESSES IN MAGNETIC MATERIALS.

Descriptive Note : Summary technical rept. Mar 64-Aug 65,

Corporate Author : RAYTHEON CO WALTHAM MA RESEARCH DIV

Personal Author(s) : Schlomann, E. ; Green, J. ; Kohane, T. ; Bierig, R.

Report Date : NOV 1965

Pagination or Media Count : 137

Abstract : The paramagnetic resonance of Yb in TmAl and TmGa garnets has been investigated. The splitting between the ground state and the first excited state inferred from the temperature dependence of the relaxation rate agrees reasonably well with the optically measured splitting. Previous work on the theory of spin-wave resonance is reviewed. It is argued that with the techniques commonly used for depositing alloy films the saturation magnetization is apt to show a linear profile due to changes in the deposition rates of the various components. The absorption spectrum to be expected in films having such a linear magnetization profile is calculated and compared to experimental data. A general theory of the permeability of ferrites having a nonuniform saturation magnetization is developed. From this general theory the static magnetization and the longitudinal permeability (response to an rf magnetic field applied parallel to the dc field) have been calculated. Experimental data obtained on porous polycrystalline YIG agree quite well with the theory. From this comparison the mean square deviation of the saturation magnetization from its average value can be determined. It was found to be consistently larger than would be expected if the host material were uniform except for the presence of nonmagnetic inclusions and/or pores. (Author)

Descriptors :   *RELAXATION TIME), (*MAGNETIC MATERIALS, IONS, YTTERBIUM, GARNET, FILMS, MAGNETIC PROPERTIES, MAGNETIC RESONANCE, SINGLE CRYSTALS, YTTRIUM COMPOUNDS, IRON COMPOUNDS, FERROMAGNETIC MATERIALS, PARAMAGNETIC RESONANCE, ATOMIC ENERGY LEVELS, THULIUM COMPOUNDS, ALUMINUM COMPOUNDS, GALLIUM COMPOUNDS, PERMEABILITY(MAGNETIC), FERRITES, PARAMAGNETIC MATERIALS, IMPURITIES, POROSITY.

Subject Categories : Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE