Hard magnetic properties of nanosized Sr(Fe,Al)12O19 hexaferrites obtained by Pechini method

In this work, we report the magnetic properties of isotropic M-type SrFe12−xAlxO19 (x=0.0,1.5) hexaferrites synthesized by means of Pechini method. A polycrystalline distribution of fine grains was verified by Transmission Electron Microscopy for both compositions, with average sizes below 60 nm. Remarkable coercivity values within the range 500-850 kA/m were attained as a consequence of a combined effect of grain size refinement together with an enhancement of the anisotropy field afforded by the incorporation of the Al3+ cations into the hexagonal crystal structure.