Structural, magnetic, and Mössbauer spectroscopy of Cu substituted M-type hexaferrites

• Published in: Materials research bulletin 2016-02, Vol.74, p.192-201
• Main Authors: Awadallah, Ahmad, Mahmood, Sami H., Maswadeh, Yazan, Bsoul, Ibrahim, Awawdeh, Mufeed, Mohaidat, Qassem I., Juwhari, Hassan
• Format: Article
• Language: English
• Subjects: ABSORPTION SPECTRA; ABSORPTION SPECTROSCOPY; ANISOTROPY; BARIUM COMPOUNDS; CERAMICS; COERCIVE FORCE; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COPPER; COPPER COMPOUNDS; FERRATES; Magnetic materials; MAGNETIC PROPERTIES; MAGNETIZATION; MATERIALS SCIENCE; Mössbauer spectroscopy; PHASE TRANSFORMATIONS; SINTERING; TRANSITION TEMPERATURE; VALENCE; X-RAY DIFFRACTION
• ISSN: 0025-5408; 1873-4227
• DOI: 10.1016/j.materresbull.2015.10.034

[Display omitted] •Single BaM hexaferrite structural phases with Cu substations were prepared.•The magnetocrystalline anisotropy decreased with Cu substitution.•The coercivity was significantly modified while the magnetization remained high.•Hexaferrites with 0.2–0.4 Cu possess properties suitable for magnetic recording.•Ionic distributions from structural refinement agreed with Mössbauer spectroscopy. BaFe12−xCuxO19 hexaferrites were prepared using ball milling and sintering at 1100°C. Refinement of the X-ray diffraction patterns was carried out to determine the structural parameters and the ionic distribution over the crystallographic sites. The preferential site occupation and valence state of Cu was consistent with the results obtained from the analysis of Mössbauer spectra. Further, the magnetic parameters of the samples were discussed in light of the structural and Mössbauer analyses. The magnetic phase transition temperature was found to decrease with the level of Cu substitution, in accordance with the reduction of the superexchange interactions. Further, the magnetic softening of the hexaferrite and the significant reduction in magnetocrystalline anisotropy with Cu substitution was consistent with the ionic distribution in the lattice. This study clearly demonstrated the feasibility of using a simple method to fabricate hexaferrites with a modified coercivity, while maintain the saturation magnetization high enough for practical applications.