Investigating the exchange-coupling interaction in nanostructure composite particles of SrFe12O19 and ZnFe2O4

Abstract

Ferromagnetic SrFe12O19-ZnFe2O4 nanostructure composite particles were synthesized by co-precipitation of chloride salts, in different stoichiometric ratios, by addition of sodium hydroxide solution. The resulting precursors were heat treated at temperatures in the range 800-1200°C for 4 h. Exchange interactions of the nanostructure composite particles were studied by use of exchange-coupling theory and plots of magnetic hysteresis. On the basis of exchange-coupling theory, the exchange interaction can be improved by increasing the soft phase content within the hard matrix. As temperature and soft phase ratio increase, the exchange interaction increases because of exchange length enhancement. The modified Brown's equation was also used to analyze the effects of exchange coupling on coercivity.