Abstract

The nanocrystalline SrFe12 O (19) materials were prepared by a sol-gel auto-combustion method using different fuels such as citric acid, dextrose, aniline, and hexamine. The combustion product obtained from all the fuels except from that of aniline show a single phase of SrFe12 O (19) materials upon annealing at 1000 C-ay/2 h. The combustion product obtained from aniline as fuel shows SrFe12 O (19) as the main phase with alpha-Fe-2 O (3) as impurity. No notable change in lattice parameters is observed due to variation in fuels for SrFe12 O (19) materials. With a little change in the NIR relative reflectance (72-85 %) on fuels, the different SrFe12 O (19) materials display high NIR reflectance in the wavelength range, 1500-2500 nm. The photoluminescence emission spectra of SrFe12 O (19) materials reveal a broad emission peak at similar to 350 nm which is reminiscent to the Ba-based hexaferrite, BaFe12 O (19). The FESEM images expose quite dissimilar morphology for the various fuels used in the synthesis of SrFe12 O (19) materials. Hysteresis loops for all the nanocrystalline SrFe12 O (19) materials observed under the applied field of +/- 1.5 T at room temperature exhibit hard ferromagnetic property. The SrFe12 O (19) materials produced from glycine and aniline as fuels exhibit highest and lowest M (s) values of 61.3 and 50.5 emu/g, respectively.