Synthesis and magnetic characteristics of crystallized ceramic in the BaO–NiO–TiO2–Fe2O3 system

Composite materials with mixed spinel nickel ferrite–barium titanate as co-existing phases have been synthesized using a conventional glass–ceramics route over a certain composition of the BaO–NiO–TiO2–Fe2O3 system. The crystallographic phases present in the composition synthesized were mainly BaTiO3 and NiFe2O3 using 2% boric acid flux while varieties of phases as NiFe2O4, Ba1.12Ti8O16, BaTi4O9 and Ni3(BO3)2 were observed using higher content of flux. Magnetic measurement of glasses crystallized at various time and temperature show that a ferromagnetic behavior is present that vary greatly as the flux content varies from 2% to 10%.A specific induction Bs = 7.6 emu/g and a permeability of 4809 at applied field 5000 Oe was reached by crystallizing the parent material at 900 °C for 4 h. The variation of the magnetic properties of the composite materials as a function of added flux, particle sizes and microstructure of the samples were investigated.