Dielectric characterization of the phase transitions in Pb1-y/2(Zr1-xTix)1-yNbyO3(0.03≤x≤0.04, 0.02≤y≤0.05)

The Curie temperature and the ideal thermal hysteresis of Pb1-y/2(Zr1-xTix)1-yNbyO3 (0.03≤x≤0.04, 0.02≤y≤0.05) ferroelectric ceramics have been investigated as a function of composition at the FRH–PC phase transition. Experimental results are analyzed using the generalized effective field approach and taking into account the composition dependence of the dimensionless parameters g and h corresponding to the second and third terms in the generalized effective field expansion. With this approach we can describe reasonably well the composition dependence of TC(x,y) at the FRH–PC transition and thermal hysteresis ΔT(x,y) in the narrow range of compositions investigated. The effects of the oxygen octahedra tilt in the dielectric constant at the FRL–FRH transition have also been investigated as a function of composition