Synthesis and magnetic study of Coa€“Al substituted calcium hexaferrite

摘要

A series of calcium substituted polycrystalline ferrite ceramics with magnetoplumbite structures were synthesized using perfect stoichiometric mixtures of oxides with chemical composition, CaAl_e?‘￥Co_e?‘￥Fe_{12a€“2e?‘￥}O₁₉ (e?‘￥ = 2a€“5), by standard ceramic technique. The variation in the values of e???_c and e?‘€_s, which depends on the additive content and the temperature, was studied by means of a vibration magnetometer. The strong variation observed in coercivity, saturation magnetization and Curie temperature with chemical composition give rise to the possibility of controlling these properties and hence applying these compounds in the millimetera€“microwave range.