Abstract-We have obtained. sintered ferrite with almost-complete shape and high dimensional accuracy by adding metallic Fe, NiO, ZnO, and CuO to Ni-Zn-Cu series ferrite. To confer this non-shrinking property on ferrite. we controlled its shrinkage during the sintering process. utilizing the expansion caused by the oxidation and complex chemical reaction of densely mixed-in metallic Fe. NiO. ZnO. and CuO. The new non-shrinking ferrite is of single-phase. high-density sintered type with an extremely low expansion/shrinkage coefficient during the sintering process of 0 -0.5 ". Its magnetic characteristics and mechanical strength are virtually identical to those of conventional sintered ferrite.

The nonlinear Thomson backscattering in a circularly polarized Gaussian laser pulse is investigated and spectral characteristics of the emission are discussed. It is indicated that the frequency of the emitted light is up-shifted by the nonlinear doppler effect. By using a properly focused laser beam or putting the electron before the focus, the variety of the nonlinear Doppler shift during the interaction can be minimized and quasimonochromatic x-rays are generated. Taking into account the emission power, the optimum situations for generating quasimonochromatic x-rays are explored.

It was found that sulfur ions dissolved in chromium dioxide up to about 3 atomic percent lowering both the Curie temperature, Tc, and the saturation magnetization, σs. As the amount of sulfur increased, the lattice constant of the crystal, a0, increased from 4.423 Å to about 4.435 Å, while no change was observed for c0. The addition of sulfur did not change substantially the size of the powder. The coercive force, Hc, at room temperature was as much as 120 Oe. The combined addition of sulfur and tellurium, however, resulted in a fine acicular powder with a coercive force higher than 400 Oersted and a Curie temperature of about 100°C. This powder has potential use in thermal duplication of magnetic tape signals.

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