Shifting of X-Ray Diffraction pattern peak on BaFe₁₂O₁₉ nanocrystalline produced by sol gel auto combustion method

Barium hexaferrite BaFe₁₂O₁₉ (BHF) is one of the great importance as permanent magnets, particularly for recording magnetic in microwave devices. Nanocrystalline BHF powders were prepared by sol gel auto combustion method in citric acid - metal nitrates system. Hence the mole ratios of Ba²⁺/Fe³⁺ were varied at 1:12; 1:11.5 and 1:11 and with pH of 7 in all cases using amonia solution. For final formation of nanocrystalline BHF, heating process was done at 850oC for 10 hours in all mol ratios of Ba²⁺/Fe³⁺. The nanocrystallite size was calculated from broadening X Ray Diffraction (XRD) peaks using Scherrer formula. XRD data shows that BHF of ratio 1:12 has the same diffraction pattern with the ratio of 1:11 especially at higher value of 2 θ. Diffraction pattern of BHF with the ratio of 1:11.5 was fitting in exactly to the standard searching match and the highest value of best Figure of Merit (FoM) is 90% with the crystallite size of 22 nm. The best FoM and crystallite size for ratio of 1:12 and 1: 11 are 88% and 56 nm respectively. The diffraction peaks of BHF with the ratio of 1:12 and 1:11 are in the right side from of 1:11.5 since the amount of impurity of both is higher (12%) than of BHF with the ratio of 1:11.5 (10%).