Electrical and magnetic studies of Ba 3Co 2Fe 23−12 xMn 12 xO 41 Z-type hexaferrites

Abstract

The electromagnetic and dielectric properties of Mn substituted Ba 3Co 2Fe 23−12 x Mn 12 x O 41 (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 Fe 2+ and Fe 3+. It was inferred that the initial permeability was sensitively controlled by the substitution of Mn because of magnetostriction compensation. Low-temperature sintered Co 2Z 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.