V. Cagan

Abstract: In the basic spinel NiFe2O4, ions of larger and larger ionic radius, Zn2+ and Cd2+, have been introduced with higher and higher concentrations. The corresponding materials of composition Ni1-xZnxFe2O4 and Ni1-xCdxFe2O4 have been prepared by using a special technologic process. The lattice constant increases linearly with the mean ionic radius in tetrahedral site. The variation of the Curie temperature due to a variation of the distance between magnetic ions is evaluated. The contribution to the Curie temperature due to the magnetic carriers distribution is shown by plotting a single intercomposition hypothetic curve. In the same way the influence upon the magnetization value of the variation of the distance between magnetic ions has been evaluated. Results obtained on spinels have been compared with those deduced from literature data in the case of garnets.

TL;DR: In this article, the Doring's equation of motion of a 180°-domain wall, when adapted to the case of pinned domain walls as in polycrystalline materials, leads to a 1/D 2 dependence of the relaxation frequency of domain walls, which has already been observed.

TL;DR: In this article, a general quantitative original law is established from measurements on series of polycrystalline ferrimagnets: the acoustic emission activity is proportional to the hysteresis losses, whatever the grain size, the composition or the measuring temperature are.

TL;DR: In this paper, the acoustic emission (AE) activity in polycrystalline YIG:Mn and Ni-Zn ferrites is proportional to the hysteresis losses, and increases with grain size, but cannot be related to the magnetostriction λ s contrary to the current theory of AE.

TL;DR: In this paper, a new class of copolymer based on aminonaphthalenesulfonic acid and aniline was synthesized and it was shown that these materials are ferromagnetic, above room temperature, consistent with temperature dependent EPR tests and magneto-optic experiments.