The polycrystalline complex compounds of (PbzEr1-z)(Zr0.06Ti0.40)(1-z/4)O-3 (z = 0.07, 0.08, 0.10) (PEZT) were synthesized using the metal-alkoxide sol-gel technique. Powder X-ray diffraction (XRD) studies of these compounds suggest that they can be formed in single-phase perovskite structure by a one-step process at a relatively low temperature. Scanning electron microscopy (SEM) analysis shows that the grains are nearly spherical and distributed uniformly in the compounds. Detailed studies of dielectric properties (epsilon, tan delta, and sigma) of the compounds as a function of temperature show a broadening of the permittivity peak and a change in transition temperature with the increase of Er3+ concentration. Analysis of the diffusivity (gamma) of the peaks in these compounds provides a value between 1 and 2. The higher value of gamma indicates the greater disordering of the system. The hysteresis loop study confirms the phase transition of the system is of second order. (C) 2000 Elsevier Science Ltd.