Details

Autor(en) / Beteiligte

• Bhandare, S.V.
• Kumar, R.
• Anupama, A.V.
• Mishra, M.
• Kumar, R. Vijaya
• Jali, V.M.
• Sahoo, B.

Titel

Effect of Mg-substitution in Co–Ni-Ferrites: Cation distribution and magnetic properties

Ist Teil von

• Materials chemistry and physics, 2020-09, Vol.251, p.123081, Article 123081

Ort / Verlag

Lausanne: Elsevier B.V

Erscheinungsjahr

2020

Link zum Volltext

Quelle

Elsevier ScienceDirect Journals

Beschreibungen/Notizen

• We report the changes in structural and magnetic properties of spinel ferrites by doping magnesium, a cation that occupies the tetrahedral site, in place of nickel that occupies the octahedral site in Co–Ni ferrite (Co0.5Ni0.5Fe2O4) ceramic. We synthesized nano-crystalline Co0.5MgxNi0.5-xFe2O4 (x = 0, 0.1, 0.2, 0.3, 0.4) ceramic powder samples by sol-gel autocombustion method followed by calcination at 600 °C in air for 2 h. X-ray diffraction (XRD) patterns of the synthesized samples confirm crystalline single-phase spinel structure with cubic symmetry (Fd-3m space group). Refined structural parameters were calculated through Rietveld refinement of the XRD patterns. The crystallite sizes for all the samples were found to be in the range of 30–38 nm. Porous morphology of the samples was clearly observed from the scanning electron micrographs. The FTIR spectra confirm the formation of the spinel phase through the observed vibrational bands assigned to the tetrahedral (Td) and octahedral (Oh) interstitial complexes in the spinel structure. Magnetic measurements indicate a decrease of saturation magnetization (Ms) with increase in concentration of Mg. Room temperature 57Fe-Mössbauer spectroscopy in association with XRD results confirmed the ferrimagnetic nature of the samples with Mg occupying the Td site, Ni occupying the Oh site and Co occupying both the Td and Oh sites in the ratio of 2:3. Using the cation occupancies, Néel's two sublattice model could explain the observed magnetic properties in our Mg doped Co–Ni ferrite samples. •Nanocrystalline Mg-doped Co–Ni-ferrite samples were prepared by sol-gel auto-combustion method.•Mg and Ni occupy the tetrahedral (Td) and octahedral (Oh) sites of the spinel structure, respectively.•Co occupies both the Td and Oh sites of the spinel structure in the ratio 2:3; Fe adjusts its occupation as required.•By Mg substitution for Ni, the coercivity remains constant but saturation magnetization decreases slightly.