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.
Origin of the magnetostriction effects from Mn3+, Co2+, and Fe2+ ions in ferrimagnetic spinels and garnets
A new model is proposed to explain the magnetostriction effects in ferrimagnetic spinels and garnets with Mn3+, Co2+, and Fe2+ ions substituted into octahedral sites. Considerable experimental evidence has revealed that small amounts of each of these ions will alter substantially the magnitude of either the λ100 or λ111 magnetostriction constant, depending on the particular ion. The theory is based on the concept that Jahn‐Teller effects produce local site distortions of tetragonal (favoring 〈100〉 axes) or trigonal (favoring 〈111〉 axes) symmetry which are able to switch among the different axes of the particular family in order to select the axis closest to the direction of the magnetic field. For Mn3+ ions, the local site distortions are expected to be tetragonal (c/a≳1), in accordance with observations in a variety of magnetic oxides where static cooperative effects are present and will produce large positive changes in the λ100 constant. With Co2+ ions the distortion is also tetragonal, but of the oppo...