Por el mŽtodo de coprecipitaci-n qu'mica se obtuvo un precursor formado por hidr-xidos y carbonatos de hierro y bario que al calcinarlo a temperaturas superiores a 730 o C se transforma en ferrita de bario. Al calcinar el precursor durante 2 horas se obtuvo la magnetizaci-n m ‡xima de 59.1 emu/g para la temperatura de 925 o C. Por el mŽtodo de microemulsi-n se obtuvo un precursor fino de hidr-xidos y carbonatos de hierro y bario que al calcinarlo a temperaturas superiores a 760 o C se

more »

... en ferrita de bario. Al calcinar el precursor durante 12 horas se obtuvo la magnetizaci-n m ‡xima de 60.5 emu/g para la temperatura de 925 o C. La coercitividad intr'nseca del polvo de ferrita de bario obtenido por microemulsi-n result-ser un 20% menor que la coercitividad intr'nseca del polvo de ferrita de bario obtenido por coprecipitaci-n. Esta menor coercitividad debe favorecer al mŽtodo de microemulsi-n para la producci-n de part'culas de ferrita de bario que sirvan como medio de grabaci-n magnŽtica perpendicular. Palabras claves: Materiales magnŽticos, nanoparticulas, ferrita de bario, microemulsion, coprecipitaci-n. Comparative study of the magnetic properties of Barium hexaferrites obtained by co-precipitation and microemulsions Using the chemical coprecipitation method a precursor formed by iron and barium hidroxides and carbonates was obtained. For calcination temperatures higher than 730 o C this precursor transforms into barium ferrite. Calcining the precursor during 2 hours a maximum magnetization of 59.1 emu/g for 925 o C was obtained. Using the microemulsion method a fine precursor formed by iron and barium hidroxides and carbonates was obtained. For calcination temperatures higher than 760 o C this precursor transforms into barium ferrite. Calcining the precursor during 12 hours a maximum magnetization of 60.5 emu/g for 925 o C was obtained. For the barium ferrite obtained by microemulsion the intrinsic coercitivity was 20% lower than the intrinsic coercitivity of the barium ferrite obtained by chemical coprecipitation. This lower intrinsic coercivity should favor the microemulsion method for producing barium ferrite particles used as perpendicular magnetic recording medium.