Magnetic and morphological study of BaZn2Fe16O27 hexagonal ferrite prepared by chemical coprecipitation method

Abstract

Polycrystalline samples of the BaZn2Fe16O27 (BaZn2-W) ferrite prepared by the chemical coprecipitation method have been examined by measuring the magnetic properties (saturation magnetization, coercive and anisotropy field, Curie temperature), thermomagnetic analysis, Mössbauer spectroscopy, and scanning electron microscopy. The correlations between the magnetic properties, the grain morphology, and the relative amounts of the various phases present in samples subjected to different heat treatments are discussed. The samples prepared by optimal heat treatment show a saturation magnetization value σs =77.7 emu/g and an anisotropy magnetic field Ha =12.5 kOe. The magnetic coercive field value is low (iHc ∼150 Oe); this may be related to the large-grain dimension (≥12 μm) of the material obtained. The Curie temperatures measured for the BaZn2-W phase vary from 370 to 410 °C depending on the heat treatment of the samples.

Synthesis of nanocrystalline Ba(CoxZn1−x)2Fe16O27 by sol–gel auto-combustion method

“…The M s of the powders demonstrates a steady increase when the calcinations temperature increases from 800 to 1200 • C and reaches a maximum of 72.30 emu/g, which corresponds well to the literature value 72-77.9 emu/g for bulk material [10,11]. The increase of M s with the calcination temperature can be attributed to the improvement of the crystallinity and phase homogeneity during calcination.…”

Structural and magnetic properties of CaMg2Fe16O27

“…The diamagnetic substitution with Mg 2+ ions lowers the magnetic moment of this minority sublattice and increases the total magnetic moment. The value of H c is found to be low (≅ 20 Oe) which may be due to formation of the W ferrite occurring at high temperature (T ≥ 1200°C) which implies a large grain growth and results in a very low coercive value (Leccabue et al 1986).…”

Tailoring of structural, electrical and magnetic properties of BaCo2 W-type hexaferrites by doping with Zr–Mn binary mixtures for useful applications

“…Having a high coercivity and moderate magnetization, hexaferrites are valuable from technological point of view. W-type hexaferrites are suitable for competing in the field of magnetism because of their high saturation magnetization as compared to the most widely used other types of ferrites [3][4][5][6][7]. Furthermore, with large magneto-crystalline anisotropy in easy axis, W-type hexaferrites are applicable for both longitudinal and perpendicular recording media.…”