Abstract: Two peaks (I、Ⅱ) of μ_i-T curve have been found in the planar anisotropic Ba(Zn_1-x Co_x)₂Fe₁₆O₂₇ hexaferrites prepared by ceramic process in this paper, and the second peak Ⅱ moves to higher temperature as Co²⁺ substitution increase, but as Cu²⁺ substitution increase it moves to lower temperature. The experiment results correspond with the influence of temperature on the magnetic crystalline anisotropic constant K_u1、K_u2、K_u3, and are a great help to improving the temperature stability of the materials.

Key words: hexaferrite, magnetic crystalline anisotropy, initiative permeability, temperature stability