SrBixLaxYxFe12-3xO19 (0.0 <= x <= 0.33) hexaferrites were produced via sol-gel auto combustion. XRD patterns show that all the samples are single-phase M-type strontium hexaferrite (SrM). The magnetic hysteresis (sigma-H) loops revealed the ferromagnetic nature of nanoparticles (NPs). The coercive field decreases from 4740 Oe to 2720 Oe with increasing ion content. In particular, SrBixLaxYxFe12-3xO19 NPs with x=0.0, 0.1, 0.2 have suitable magnetic characteristics (sigma(s) = 62.03-64.72 emu/g and H-c = 3105-4740 Oe) for magnetic recording. The intrinsic coercivity (H-ci) above 15000 Oe reveals that all samples are magnetically hard materials. Tauc plots were used to specify the direct optical energy band gap (E-g) of NPs. The E-g values are between 1.76 eV and 1.85 eV. Fe-57 Mossbauer spectroscopy data, the variation in line width, isomer shift, quadrupole splitting, relative area and hyperfine magnetic field values on Bi3+ La3+ and Y3+ substitutions have been determined. (C) 2016 Elsevier Ltd. All rights reserved.