The effect of surfactant hydrocarbon tail length on the crystallite size of Sr-hexaferrite powders synthesized by a sol–gel auto-combustion method

Abstract

In this work a novel sol–gel auto-combustion method has been used to synthesize nanocrystalline Sr-hexaferrite powder. The gels were prepared from metal nitrates, citric acid and trimethylamine as a pH-adjusting agent without any surfactant and with various cationic surfactants such as n-decyltrimethylammonium bromide, n-dodecyltrimethylammonium bromide, n-tetradecyltrimethylammonium bromide and n-cetyltrimethylammonium bromide, which are different in hydrocarbonic tail length. Results showed that applying surfactant, particularly with longer hydrocarbonic tail, results in smaller crystallite size and narrower particles size distribution.