Enhanced dielectric relaxation behavior of Zr doped Ba^sub 0.9^Ca^sub 0.1^Zr^sub x^Ti^sub 1-x^O3-0.03Bi^sup 3+^ ceramics

J Mater Sci: Mater Electron (2015) 26:12751281 DOI 10.1007/s10854-014-2537-3

Enhanced dielectric relaxation behavior of Zr doped Ba0.9Ca0.1ZrxTi12xO30.03Bi3+ ceramics

Zixiong Sun Yongping Pu Chenfei Zhang

Received: 31 July 2014 / Accepted: 18 November 2014 / Published online: 25 November 2014 Springer Science+Business Media New York 2014

Abstract The enhancement of dielectric relaxation behavior of lead-free Zr4? doped Ba0.9Ca0.1ZrxTi1-xO3

0.03Bi3? ceramics prepared by hydrothermal method were studied. The XRD patterns and calculated lattice parameters both indicated a phase transition from tetragonal to cubic phase with x increasing from 0.00 to 0.12. And the increasing Zr exhibits the homogenization of grain size from SEM patterns. Compositions of x = 0.00 and 0.03 were normal ferroelectrics with sharp Tm peak while the samples exhibit strong relaxation behavior at x = 0.09 and0.12 and the relaxation parameters were calculated. Thus the lead-free Ba1-xCaxTi1-xZrxO3 system relaxor ferroelectrics were obtained. The PE loops of all these samples can be divided into two types: the broad and the narrow, which was probably attributed to the grain size and phase transition at room temperature.

1 Introduction

Due to of advantages of high piezoelectric constant (d33)

especially environment-friendly, BCTZ system piezoelectric have attracted much interests and were widespread in sensors, actuators, transducers, resonators, etc. Over the past several decades, the research emphasis all over the world of BCTZ system ceramics is located in the

improvement of d33 through modifying the Ba/Ca and Ti/ Zr and preparation technology. Up to now, the d33 of BCTZ

system ceramics reached up to over 500 pC/N, which maybe the bottleneck and the further improvement is difcult to obtain [16]. Nevertheless, a being ferroelectrics, the relaxation behaviors of BCTZ ceramics were barely mentioned in current studies. In present study, Ba0.9Ca0.1ZrxTi1-xO30.03Bi3? ceramics with different

x were prepared via conventional hydrothermal method and optimism relaxation behaviors were obtained at higher x [3, 711].

Instead of normal ferroelectrics, relaxor ferroelectrics have generic features of: broad maximum in temperature dependence of the dielectric permittivity, whose position, Tm, is shifted to lower temperatures as the frequency of the probing eld decreases; modied CurieWeiss law and the detection of ferroelectric hysteresis loop (PE loop) at higher temperature (above Tm). In this work, the gradually transform from normal ferroelectrics to relaxor ferroelectrics with increasing Zr content can...