A quaternary lead based perovskite structured materials with diffuse phase transition behavior

A lead based quaternary compound composed of 0.25(PbZr0.52Ti0.48O3) + 0.25(PbFe0.5Ta0.5O3) + 0.25 (PbF0.67W0.33O3) + 0.25(PbFe0.5Nb0.5O3) – (PZT–PFT–PFW–PFN) was synthesized by conventional solid-state reaction techniques. It showed moderate high dielectric constant, low dielectric loss, and two diffuse phase transitions, one below the room temperature ∼261 K and other above ∼410 K. X-ray diffraction (XRD) patterns revealed a tetragonal crystal structure at room temperature where as scanning electron micrograph (SEM) indicates inhomogeneous surface with an average grain size of 500 nm–3 μm. Well saturated ferroelectric hysteresis loops with good saturation polarization (spontaneous polarization, Ps ∼ 30.68 μC/cm2) were observed. Temperature-dependent ac conductivity displayed low conductivity with kink in spectra near the phase transition. In continuing search for developing new ferroelectric materials, in the present study we report stoichiometric compositions of complex perovskite ceramic materials: (PZT–PFT–PFW–PFN) with diffuse phase transition behavior. The crystal structure, dielectric properties, and ferroelectric properties were characterized by XRD, SEM, dielectric spectroscopy, and polarization. 1/ɛ versus (T) plots revealed diffuse relaxor phase transition (DPT) behavior. The compositional variation on the phase transition temperature, dielectric constant, and ferroelectric to paraelectric phase transitions are discussed.

(a) Curie–Weiss plot for the inverse of the relative dielectric permittivity and (b) log (1/ɛ − 1/ɛm) as function of log (T − Tm) for ceramics at 1 kHz.Figure optionsDownload as PowerPoint slideHighlights
► Retaining phase pure structure with quaternary complex stoichiometric compositions.
► P–E loops with good saturation polarization (Ps ∼ 30.7 μC/cm2).
► Diffused relaxor phase transition behavior with γ estimated is ∼1.65.