The interesting functions of additives in NiZn-ferrite
introduction Additives play a quite significant roll in microwave ferrites. Proper sorts and quantities of additives can improve aany important characteristics of materials. In this paper, two kinds of additives,NW and cd). are discxlssed about their effects on tk remanent ratios R of NiZn ferrites used in milliaeter-wave band. Both of them can enhance R efficiently so that they are beneficial to latching device applications. The mechanism is discussed qualitativeiy.At the same tile,scnoe interesting attendent phenomena are rqnrted. ExDeriments The specimens were prepared with wnventional ceramic process with the composition as follows: NILCo. Zb., CU, Bim Nb. & Fel.s 0, (1) The B-Hloops were traced with a YEW W e 1 3251 Auto Tracer. The raoanent ratics +R/R were read off the loops of sa!41ples,whose mercive forces were around 80 A/m (1 Ce), with the magnetizing field H,-3Z@A/n(40 Oe).B and B, are residual and saturation inductions,respectively.
Magnetostriction of Ni-Zn ferrites containing cobalt
Abstract The influence of a small cobalt content on the magnetostriction of Ni-Zn ferrites has been investigated and is discussed. It is shown that, as in the case of a magnetocrystalline anisotropy, the value of λ s may in this case be quite different from that expected. The results prove that, in spite of common opinion, there are no “piezomagnetic obstacles” to introducing Co ions into Ni-Zn ferrites, when the diminishing of their magnetic loss factor in high frequency range is needed.
Anisotropy and Magnetostriction in Magnetic Oxides
Recent theories of the anisotropy and magnetostriction due to the presence of Co2+ in spinel ferrites are reviewed and new work on the effects of Fe2+ is presented. The effects of these ions are great because the orbital angular momentum is not fully quenched by the crystal field. In the case of Co2+, the orbital moment of the ground state is coupled strongly to the trigonal axis of the crystal field. The very large anisotropy and magnetostriction arise from spin-orbit coupling in first order. The theory is found to account for many of the effects of cobalt-iron ferrite and cobalt-manganese ferrite at higher temperatures. The contribution of Fe2+ to these effects is less extreme but still striking. Here the orbital moment is more nearly quenched but the spin is still coupled strongly to the trigonal axis. The coupling gives rise to cubic anisotropy in second order approximation. This term appears to account for the large compositional dependence of anisotropy in manganese-rich manganese-iron ferrite. A cr...