SrZn_xFe_2−x-W型六方晶フェライトの生成条件及び磁気物性に関する研究

抄録

The formation conditions (temperature and oxygen partial pressure) of SrZn_xFe_2−x-W-type ferrites (SrZn_xFe_18−xO₂₇, 0 ≤ x ≤ 2) were investigated. W-type ferrites were formed under higher oxygen partial pressure when sintering temperature became higher. The oxygen partial pressure for forming the ferrites also increased when the Zn content x increased. The site distribution of iron and zinc ions was determined from Rietveld analysis of synchrotron radiation X-ray diffraction and the extended X-ray absorption fine structure (EXAFS) analysis at Zn-K edge. The Rietveld and EXAFS analyses indicated that zinc ions occupied mainly the 4e and 4f_IV sites, which were tetrahedral ones with down spin. Saturated magnetizations of the ferrites at 3 K increased with the increasing of the zinc content x. The magnetic moments of Fe³⁺ and Fe²⁺ are estimated to be 4.45 and 3.70 μ_B at 3 K in the ferrites, respectively.