Preparation and characterisation of the Ba(Zr,Ti)O(3) ceramics with relaxor properties

Abstract

Ba(Zr(x)Ti(1-x))O(3) ceramics with various compositions x in the range (0, 0.5) have been prepared via solid state reaction. Optimum parameters for calcination and sintering have been found in order to obtain pure perovskite phase and high density ceramics. The dielectric data showed a transition from ferroelectric towards relaxor state and a shift of the Curie temperature towards lower values with increasing x. Using the modified Landau model for relaxors, the local order parameter has been calculated. Its temperature dependence shows the increasing of the degree of diffuseness of the phase transition with increasing Zr with a maximum for the composition x=0.35. The model also shows that in the relaxor state the local order parameter has non-zero values even at a few hundreds degrees above the temperature corresponding to the maximum of the dielectric constant. Further, the dielectric data obtained for x=0.35 under field cooling (FC) and zero-field cooling (ZFC) conditions shows a splitting characteristic to the relaxors and spin-glass systems