Magnetic Structure and Spin-Orientational Transitions of Hexaferrites of the BaCo2−xZnxFe16O27 System

Abstract

A neutronographic study is made of magnetic structure and spin‐orientational transitions in polycrystalline samples of the system BaCo2−xZnxFe16O27 (Co2−xZnxW). Along with this studies measurements of the macroscopic magnetic characteristics, X‐ray dilatometry, and DTA are performed. The diagram of the magnetic state is plotted in the coordinates: content‐temperature. The compounds with Zn2+ ion content, 0 ≦ x ≦ 1.6 exhibit the sequence of orientational phase transitions coneplane‐cone‐axis of easy magnitization when the temperature increases. The order of these transitions is determined and the role of Co2+ ions for creation of planar anisotropy in oxide ferrimagnetics with hexagonal structure is discussed.

The Process Automation of Temperature Measurement by Measuring Facility Which is Consists from Agilent E8363B and Freezer/Heating Chamber TNC-80

“…To establish correct functioning of the Virtual Instrument program it is necessary to measure the effect of temperature on the magnetic permeability of W-type hexaferrite powder [5]. The hexaferrite powder was put into quartz tube with inner diameter 2 mm.…”

“…Figure 4 shows the calculation results. In order to provide an interpretation of the magnetic permeability results, we will use a data from article [5]. This article shows, that W-type hexaferrite bulk sample have nonlinear temperature dependence of magnetic permeability.…”

Structure parameters and magnetic properties of Me2W1 cobalt-containing hexaferrite systems synthesized by the SHS method

“…It is natural that with increasing cobalt ion content, the spin reorientation phase transition from EMD to EMP type anisotropy will be observed in solid solutions of the Co 2+ -containing hexaferrites combined with any of the above-listed ions. We note that these transitions are observed not only for concentration but also for temperature changes [2][3][4]. Neutron-diffraction investigations of Co 2-x Zn x W system hexaferrites carried out in [3] have demonstrated that the EMD ↔ EMP temperature spin reorientation transition proceeds through the easy magnetization cone (EMC) phase.…”

“…We note that these transitions are observed not only for concentration but also for temperature changes [2][3][4]. Neutron-diffraction investigations of Co 2-x Zn x W system hexaferrites carried out in [3] have demonstrated that the EMD ↔ EMP temperature spin reorientation transition proceeds through the easy magnetization cone (EMC) phase. The anisotropy fields can change in a wide range with changes of the Co 2+ ion concentration, which offers possibilities of W-type hexaferrite application for EWA in the entire microwave range starting from ~1 GHz [4,5].…”

“…The measured temperatures of the EMP ↔ EMC spin reorientation transitions (Т pl.-cone ) and T C for the examined powders are presented in the last two columns. The corresponding temperatures for the samples synthesized by the conventional ceramic technology [3] are given in the parentheses.…”