M-Type Hexaferrites With Enhanced Coercivity

In this work, we report the synthesis, structure and magnetic properties of SrFe
₁₁
T
₁
O
₁₉
(T = Ga,Cr,In,Al) hexaferrite powders obtained by Pechini method. For all the samples, formation of the M-type structure was verified, together with a significant grain size coarsening, from 100 to 3000 nm. The magnetic properties include remarkable coercivity values of up to 590 kA/m, together with Curie temperatures within the range 652 K to 730 K across the compositional series. The coercivity variation was explained in terms of the evolution from single-domain magnetic particles to multidomain particles as a consequence of the significant grain growth.