tailieunhanh - Effect of on structure and ferroelectric properties of BZT-BCT material

In this paper, we report the effect of Ca substitution on the structure and ferroelectric properties of (BZT-BCT). The BZT-BCT samples were synthesized by solid state reaction method. The X-ray results indicate that a phase structure competition appears in the Ca-substituted samples. | Vietnam Journal of Science and Technology 56 (1A) (2018) 86-92 EFFECT OF Ca CONCENTRATION SUBSTITUTING FOR Ba ON STRUCTURE AND FERROELECTRIC PROPERTIES OF BZT-BCT MATERIAL Nguyen Văn Khien1, Le Van Hong2, 3 1 Thai Nguyen University of Sciences, Tan Thinh Ward, Thai Nguyen City, Viet Nam 2 Duy Tan University, K7/25 Quang Trung, Da Nang City, Viet Nam 3 Institute of Materials Science, VAST, 18 Hoang Quoc Viet, Cau Giay, Ha Noi, Viet Nam * Email: Received: 15 August 2017; Accepted for publication : 5 March 2018 ABSTRACT In this paper, we report the effect of Ca substitution on the structure and ferroelectric properties of (BZT-BCT). The BZT-BCT samples were synthesized by solid state reaction method. The X-ray results indicate that a phase structure competition appears in the Ca-substituted samples. Based on the hysteresis loops measured by Sawyer – Towermethod, we calculated the Ec and Pr values with the extreme value reaching %. The ferroelectric properties of BZT-BCT materialstrongly depend on Ca concentration. The results may be related to a pinning effect concerning with the phase-structured competition in the material. Keywords: BZT-BCT, substitution, ferroelectric, phase structure competition. 1. INTRODUCTION Ferroelectric property in perovskite materials comes from the combination of the movements of atoms in cubic structure. In BaTiO3 (BTO), spontaneous polarization (Ps) is induced by the deflection of Ti off the orthohedral of O site resulting the hybridization between Ti - 3d and O - 2p. The spontaneous displacement of Ba in BTO is so small because of the strong Ba-O bonding [1]. Inversely, in PbTiO3, Pb-O bondings are the hybridization between the Pb-6s and the O-2p [1, 2]. Recently, the replacement of Ca for Ba in BTO has attracted many attentions due to its interesting properties, especially its piezoelectric property. The first report on Ba1-xCaxTiO3 (BCT) composite [3, 4] showed that the .