Electrical and magnetic studies of Ba3Co2Fe23−12xMn12xO41 Z-type hexaferrites

The electromagnetic and dielectric properties of Mn substituted Ba3Co2Fe23−12xMn12xO41 (Z-type) hexaferrites where 0≤x<0.1 were investigated in this study. The ferrite samples behaved as a semiconductor, and DC resistivity as well as activation energy for electronic conduction increased as the amount of Mn substituted for Fe increased, reaching maximum around x=0.02, and then decreased with further substitution. The behavior of dielectric constant was in an opposite manner to that of the activation energy and DC resistivity. Conduction is explained on hopping of electrons between Fe2+ and Fe3+. It was inferred that the initial permeability was sensitively controlled by the substitution of Mn because of magnetostriction compensation. Low-temperature sintered Co2Z hexaferrite with the substitution of Mn for Fe with low dielectric constant and high initial permeability is suitable for very high frequency (VHF; 300–800 MHz) multilayer chip inductors (MLCI) use.