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SrFe12O19 samples were initially prepared using sol-gel auto-combustion method and calcined from 500 to 1100°C (for 6 h). XRD data established the phase formation temperature of SrM phase to be ≈1000°C. Thereafter, the effect of Zn2+-Zr4+ co-dopant on magnetic and structural properties of SrZnxZrxFe12-2xO19 (x = 0.00–1.00) samples calcined between 900–1100°C was investigated. XRD data shows that the cell volume increases (from 690.45Å3 (x = 0.00) to 705.72Å3 (x = 1.00)) while crystallite size decreases (from 123.9 nm (x = 0.00) to 62.3nm (x = 1.00)) calcined at 1000°C. The Rietveld refinement of XRD data confirms a) x = 0.00 sample to be phase pure and b) the presence of ZnFe2O4 (≈2.25) & SrZrO3 (≈2.93%) impurity phases in x = 1.00 sample, calcined at 1000°C. FESEM micrographs revealed that a) grain size decreases for x > 0.20 with `x’ at 900°C and b) increases from 122 nm at 900°C to 443 nm at 1100°C, for x = 0.00. Broadening of Raman bands reveals generation of strain in the lattice with enhancement of Zn2+-Zr4+ concentration. The magnetic studies reveal that the coercivity monotonically decreases (from 5358(x = 0.00) Oe to 690(x = 1.00) Oe at 1000°C) with enhancement of Zn2+-Zr4+ concentration. A maximum Ms value ≈ 70.89 emu/g was observed in x = 0.20 sample at 1100°C. Ms value also decreases for x > 0.20 at each calcination temperature.

M-type barium hexaferrite (BHF) is frequently used for permanent magnet preparation. Herein, we have synthesized BHF via sol–gel-auto-combustion route using Jamun pulp which perform multiple functions such as natural fuel, green reducing agent and ecofriendly chelating agent. The effect of Jamun pulp concentration (10–60 g/100 mL of water) on structural, morphological properties, coercivity and the saturation magnetization of BHF has been studied for the first time. The X-ray diffraction (XRD) analysis confirmed phase purity of BHF (i.e. absence of even traces of intermediate phase (α-Fe2O3 and BaFe2O4.) at 50 g/100 mL of water and higher Jamun pulp concentration. Further, the c/a ratio

We report the synthesis of Ba0.5Sr0.5ZnxZrxFe12-2xO19 (x = 0.00–1.00) samples using sol–gel auto combustion method. The Rietveld refinement of XRD data indicates a) pure phase formation, b) increase in lattice parameters with composition and c) the absence of undesirable phases such as α–Fe2O3, BaCO3 and SrCO3. FESEM and TEM micrographs reveal an increase in grain size with ‘x’. The broadening of Raman peaks without any peak shift in all the samples indicates that the Zn2+/Zr4+ions are incorporated into Ba0.5Sr0.5Fe12O19 without altering the local structure. Magnetic measurements reveal that the maximum value of saturation magnetization (Ms) is 67.37 emu/g in x = 0.4 sample. The coercivity (Hc) monotonically decreases from 4.936 KOe to 1.029 KOe with increasing concentration of non-magnetic dopants. The dielectric constant values decreases monotonically as function of frequency for all the samples. The samples because of their superior magnetic properties could be vital for high density perpendicular recording, high density parallel recording EM shielding and permanent magnet applications.