Microstructure and magnetic properties of Y substituted M-type hexaferrite BaY x Fe 12−x O 19

Y (yttrium)-substituted M-type hexaferrite of composition BaY x Fe 12−x O 19 (x ranges from 0.1 to 0.8 with step of 0.1) was synthesized through ceramic process. Pure phase formation of M-type hexaferrite was confirmed by XRD patterns for prepared sample when x < 0.4. The second phase (Y 3 Fe 5 O 12 ) was detected when the substitution content exceeded 0.4. As the substitution dosage of yttrium increased, unconspicuous transform were observed in the microstructure of all samples BaFe 12−x Y x O 19 , such as compactness, size of grain. The bulk densities ( ρ ) of the samples decreased first and then increased with the increase of X. It means that the compactness of the sample receded first and then enhanced with rise of Y 3+ substitution contents. Moreover, with increase of Y 3+ amount, Y 3+ substituted the Fe 3+ in the octahedral position of m-type barium ferrite, the saturation magnetization ( M s ) of the sample decreases rapidly and obtained a minimum of 55.63 emu/g, and then increased gradually attributed to the appearance of the second phase (Y 3 Fe 5 O 12 ). Appropriate values of M s (56.57 emu/g) and H c (1794.17 O e ) were obtained simultaneously when x = 0.6. These two characters made the material suitable for the applications infield of magnetic recording.