Vol.:(0123456789) 1 3 Journal of Materials Science: Materials in Electronics https://doi.org/10.1007/s10854-019-02330-9 Role of Y 3+ ion substitution in the enhanced electrical properties of Ba (0.9−x) Y x Ca 0.1 Zr 0.07 Ti 0.93 O 3 lead‑free piezoceramics Shreya Mittal 1  · Ishita Chaturvedi 1  · K. Chandramani Singh 1 Received: 11 August 2019 / Accepted: 9 October 2019 © Springer Science+Business Media, LLC, part of Springer Nature 2019 Abstract Ba (0.9−x) Y x Ca 0.1 Zr 0.07 Ti 0.93 O 3 lead free piezoelectric ceramics were synthesized for x = 0–0.035 in the steps of 0.005. The lead free piezoceramics are gaining importance as there is an urgent demand for replacing the highly toxic PZT family piezoceramics. Ba 0.9 Ca 0.1 Zr 0.07 Ti 0.93 O 3 (BCZT) is one such system. It shows some high electrical properties but sufers with a low Curie temperature, which restricts its usage in low temperature range only. In the present study, the Curie temperature has been improved by 9 °C. A polymorphic phase transition (PPT) has also been observed around x = 0.015, consisting of orthorhombic and tetragonal phases, which provides the polarization vector more number of favorable directions. As a result the remnant polarization (P r ), piezoelectric charge coefcient (d 33 ) and electromechanical coupling coefcient (k p ) attain their maximum values of 5.21 μC/cm 2 , 200 pC/N and 24.78% respectively for x = 0.015. This increase in transition temperature and other electrical properties makes BCZT a potential candidate for a lead free piezoelectric system. 1 Introduction Piezoelectric ceramics have been in use for many years, due to their wide area of applications. These applications include actuators, sensors and transducers. One of the most widely used piezoceramic is lead zirconium titanate (PbZr x Ti 1−x O 3 ), abbreviated as PZT, which is a lead based composition. But, lead, being the hazardous substance, must be and has already been banned from almost all of the industries. It is well known that its use can cause serious health issues, including cancer [1]. For many years, the search for a lead- free piezoelectric composition has been going on. But, a suitable candidate has not yet been found; this forced the European countries to implement RoHS 2017 that restricts the use of all hazardous substances except PZT (Lead zirco- nium titanate) in the electronic industry, to be replaced by a suitable candidate by 2022 [2]. Such exemption calls for the urgent need of fnding a lead-free piezoelectric replace- ment for highly toxic lead-based PZT. In 2009, Liu et al. were able to introduce the world to a lead free composition x[Ba(Zr 0.2 Ti 0.8 )O 3 ] − (1 − x)[(Ba 0.7 Ca 0.3 )TiO 3 ], abbreviated as BZT-BCT, with comparable piezoelectric properties to the existing prevalent piezoceramic, PZT [3]. Since the dis- covery of the BZT-BCT composition, a lot of eforts have been made to further improve its electrical properties. Most of these studies include optimizations in the sintering condi- tions and techniques [4–7], tailoring the initial particle size [8–12] and doping with suitable elements at A-site, B-site or simultaneously both sites [13–17]. But, the major drawback associated with this composition is its low Curie tempera- ture, which restricts its usage in low temperature range only. In one of our previous studies, we synthesized Ba 0.9 Ca 0.1 Zr 0.07 Ti 0.93 O 3 − xY (x = 0, 0.02, 0.04, 0.06, 0.08, 0.1) ceramics in which yttrium was freely doped to enter any of the possible sites [18]. We observed that yttrium enters A-site with Ba 2+ vacancies for x = 0.02 only and after that it enters B-site with Ti 4+ vacancies for x = 0.04 to x = 0.1. Also, we observed that A-site substitution of yttrium resulted in elevated Curie temperature with improved electrical proper- ties. The increase in Curie temperature was the highlight of the previous study as the low Curie temperature is the major drawback of BCZT compositions. The enhanced results were attributed to the multi-phase coexistence region in A-site substitution of Y 3+ . The present study is to see the efect of A-site substitu- tion, with change in the concentration of Y 3+ , on the tran- sition temperature and electrical properties of BCZT composition. For this, we synthesized and investigated Ba (0.9−x) Y x Ca 0.1 Zr 0.07 Ti 0.93 O 3 (x = 0, 0.005, 0.01, 0.015, 0.02, * K. Chandramani Singh kongbam@gmail.com 1 Department of Physics, Sri Venkateswara College, University of Delhi, New Delhi 110021, India