Effect of Nb doping on microstructure and electric properties of lead zirconate stannum titanate antiferroelectric ceram

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a) Z. Xu, and C.H. Zhang Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, Xi’an Jiaotong University, Xi’an 710049, People’s Republic of China

J.Q. Gao State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, People’s Republic of China (Received 9 October 2008; accepted 11 February 2009)

The aim of this work is to study the effect of Nb element doping on the microstructure and electrical properties of lead zirconate stannum titanate (PZST) ceramic and to improve phase transition properties of PZST. Nb-doped Pb(Zr,Sn,Ti)O3 ceramic samples were prepared by the conventional mixed oxide method. Phase transitions induced by temperature, pressure, and electric field were measured with electric dielectric permittivity, hydrostatic pressure, and hysteresis. The microstructure of the samples was observed by electron scanning microscope to discuss the effect of Nb doping on PZST ceramics. The experiment results indicated that the remnant polarization (Pr), dielectric constant, phase transition, and microstructure were strongly dependent on Nb doping content. I. INTRODUCTION

Lead zirconate stannate titanate (PZST) family of ceramics was first investigated by Berlincourt1 in the 1960s and has been widely studied since then. It is known that the antiferroelectric phase can be switched to the ferroelectric phase with the application of an electric field and the ferroelectric phase can be switched back to antiferroeclectric phase with the application of heat and stress. The antiferroelectric to ferroelectric phase transition is accompanied by a large volume strain, which has been of interest for high performance actuators and transducers. The antiferroelectric to ferroelectric phase transition induced by stress or shock wave can release high electric charges instantly, which has been used in pulsed power application and energy conversion devices. The ferroelectric to antiferroelectric (FE-AFE) phase transition pressure in PZT95/5 and La-doped PZST ceramics at room temperature occur at 200 and 110 MPa, a)

Address all correspondence to this author. e-mail: [email protected] This paper was selected as an Outstanding Symposium Paper for the 2008 International Materials Research Conference, Symposium F. DOI: 10.1557/JMR.2009.0202

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J. Mater. Res., Vol. 24, No. 5, May 2009 Downloaded: 31 Mar 2015

respectively.2–4 Furthermore, the effect of composition and temperature on FE-AFE phase transition pressure of Nb-doped PZST ceramics has been studied.5 Nb-doped PZST ceramics at room temperature have different structures, such as orthorhombic antiferroelectric phase (AFEO), tetragonal antiferroelectric phase (AFET), lowtemperature rhombohedral ferroelectric phase (FERL), high-temperature rhombohedral phase (FERH), tetragonal ferroelectric phase (FET), and cubic paraelectric phase (PEC). It is proposed that the Pb vacancies introduced by Nb doping would facilitate the solid state reactions, leading to ceramics with higher d