High-temperature ferromagnetic resonance (FMR) in FePt-based media materials was studied for the first time. The FMR linewidth (ΔH) as a function of temperature (T), field angle (θ H), and the volume fraction (x) of carbon in the material were determined, and the effective Gilbert damping constant and the Bloch-Bloembergen relaxation time were estimated. The data suggest that at temperatures 10-45 K below the Curie temperature, two-magnon scattering and spin-flip magnon-electron scattering make comparable contributions to ΔH. With a decrease in T, ΔH increases due to enhancement of the two-magnon scattering. ΔH can be tuned via varying x and shows a maximum at θ H ≈45° when varying θ H .

A study of the decay of tension of Columbia 56's wool fibers maintained at constant temperature and extension has been carried out in water, in solutions of sodium bisulfite of various concentrations, and in neutral salt solutions.The experimental results obtained in water are similar although not identical to the results previously found by Speakman and Shah for human hair. The rapid stress decay of stretched wool which occurs when sodium bisulfite is added appears to be due to a chemical reaction involving the cystine linkages. The rate becomes independent of bisulfite concentration at sufficiently high concentrations. A much slower but unexpectedly large stress decay occurs in the presence of neutral salts such as sodium chloride.

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The reaction of polymeric media with a chemical reagent generally involves the preliminary diffusion of the reagent through the polymer. The effect of a relatively rapid diffusion of a chemical reagent into a cylindrical fiber on the over all rate of reaction is considered and the equation therefor is derived. The equation is applicable both to the extent of the reaction and to the decay of stress in the polymer, provided that a linear relationship between stress and extent of reaction is assumed.