DOI: 10.1007/s00339-006-3486-3 Appl. Phys. A 83, 295–299 (2006) Materials Science & Processing Applied Physics A s. eitssayeam u. intatha g. rujijanagul k. pengpat t. tunkasiri ✉ Structural and electrical properties characterization of (1–x)PbZr 0.52 Ti 0.48 O 3 –xBaFe 0.5 Nb 0.5 O 3 system Department of Physics, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand Received: 18 May 2005/Accepted: 17 December 2005 Published online: 27 January 2006 • © Springer-Verlag 2006 ABSTRACT The structural and electrical properties of (1 − x )PbZr 0.52 Ti 0.48 O 3 –x BaFe 0.5 Nb 0.5 O 3 ceramics system with the composition near the morphotropic phase boundary were investigated as a function of the BaFe 0.5 Nb 0.5 O 3 con- tent by X-ray diffraction (XRD) and dielectric measurement technique. Studies were performed on the samples prepared by solid state reaction for x = 0.1, 0.2, 0.3, 0.4 and 0.5. The XRD analysis demonstrated that with increasing BFN content in (1−x )PZT–x BFN, the structural change occurred from the tetragonal to the cubic phase at room temperature. Changes in the dielectric behavior were then related to these structural depending on the BFN content. PACS 77.84.Dy; 77.22.Ch; 77.22.Gm 1 Introduction Pb(Zr x Ti 1−x )O 3 (generally known as PZT) is a solid solution of perovskite ferroelectric PbTiO 3 and antiferroelectric PbZrO 3 . The PZT has been considered as an important material for a wide range of piezoelectrics, pyroelectrics and ferroelectrics device applications such as transducers, memory chip, transformer and pyro- electric sensors [1, 2]. Since the discovery of relaxor be- havior in Pb(Mg 1/3 Nb 2/3 )O 3 [3], Pb(Zn 1/3 Nb 2/3 )O 3 [4], Pb(Ni 1/3 Nb 2/3 )O 3 [5] and Ba(Fe 0.5 Nb 0.5 )O 3 [6, 7]. The stud- ies of relaxor ferroelectrics with AB ′ (1−x) B ′′ x O 3 -type perovskite have attracted much attention because of their excellent dielectric and electromechanical properties. Pb(Zr 0.52 Ti 0.48 )O 3 and Ba(Fe 0.5 Nb 0.5 )O 3 belong to the per- ovskite structural family with general formula ABO 3 (A = mono or divalent ions, B = tri- to pentavalent cations). It is well established that the physical properties or device parame- ters of PZT can be tailored by synthesizing the materials with improved processing techniques and making suitable substi- tutions of A and/or B sites. The electrical properties of relaxor ferroelectrics are greatly influenced by the manner in which the B site cations (B ′ and B ′′ ions) are distributed and ordered on the B site sublattice. The Zr/Ti ratio is known to strongly influence properties, such as the elastic constant, the dielectric constant, the coupling factor, etc. ✉ Fax: +66-5335-7512, E-mail: tawee@chiangmai.ac.th In spite of the evident effect of the BFN on the PZT by solid state reaction, the phase evolution and behavior of elec- trical properties of dense ceramic bodies of materials obtained by the solid state reaction are not clearly understood. There- fore, we decided to prepare (1−x )PZT–x BFN (x = 0.1 to 0.5) powders and subjected the sintered to an extensive characteri- zation and microstructure and dielectric properties. 2 Experimental The PZT–BFN ceramics used in this study are prepared from powders using the conventional mixed- oxide method. The (1−x )PbZr 0.52 Ti 0.48 O 3 –x BaFe 0.5 Nb 0.5 O 3 (1−x PZT–x BFN) powders were first prepared by mixing the starting materials PbO (> 99%), ZrO 2 (> 99%), TiO 2 (> 99%), BaCO 3 (> 99%), Fe 2 O 3 (99.9%) and Nb 2 O 5 (99.9%) powders in the desired mole ratio, (x = 0.1, 0.2, 0.3, 0.4 and 0.5). These powders were ball-milled for 24 h in polyethylene container with zirconia balls. Ethanol was used as a milling medium. After drying at 120 ◦ C, the mixed powders were then calcined at 800– 1100 ◦ C for 2h with heating and cooling rate of 5 ◦ C/min. Subsequently, the most appropriate calcined samples were pressed into disc shape and sintered at vari- ous temperatures ranging from 1150 to 1300 ◦ C depending upon the compositions. The samples were heated for 2h with constant heating and cooling rates of 5 ◦ C/min. The physical characteristics of the ceramics were then determined with the following procedures. The densities of the sintered ceramics were measured by Archimedes method. The phase forma- tions of the calcined powders and sintered specimens were studied by an X-ray diffractometer (Philips model X-pert) at 40 kV and 30 mA in the 2θ range from 10 to 60 degrees with step scan of 0.01 ◦ . The microstructure was examined by the scanning electron microscopy (Jeol model 6335F). For electrical property characterizations, the sintered sam- ples were ground to obtain parallel faces, and the faces were then coated with silver paste as electrodes. The samples were heat-treated at 750 ◦ C for 12 min to ensure the contact be- tween the electrodes and the ceramic surfaces. The dielec- tric constant and loss tangent of the sintered ceramics were measured as a function of temperature at 1 kHz with an auto- mated dielectric measurement system. The system consists of an LCR-meter (Hioki 3532-50) and a furnace tube, both furnace temperature and dielectric properties were controlled and recorded by a computer. The capacitance and the di-