The influence of the substitution of copper for cobalt on the low-sintering densification, microstructure, lattice parameters, and electromagnetic properties of planar Z-type hexaferrites, which have a stoichiometric composition of Ba3Co2(10.8-x)- Zn0.4Cu2xFe24O41, were investigated. The experimental results show that densification of the copper-substituted hexaferrite is dependent on the amount of copper substitution and sintering temperatures. XRD analysis reveals that the solid solubility of copper in Z-type hexaferrite is limited to x less than or equal to 30. At the same time, the lattice parameters (a and c) of Z-type hexaferrites with copper substitution showed a small change, that is, decrease of a parameter in the basal plane and increase of the c axial. Moreover, the microstructure becomes more homogeneous and intragranular pores decrease considerably, but the temperature-stable range of the Z-type phase formation is narrow. The copper-substituted hexaferrites, with x = 0.20 and sintered at similar to1125degreesC for 4 h, resulted in a high density sample of similar to4.68 g/cm(3) as the optimal value, good magnetic properties, and the enormous potentiality for fabrication of multilayer chip inductors used in hyper-frequencies.