Multi-functional perovskites – an investigation of compositional and processing influence on microstructure, dielectric and ferroelectric properties
Microelectronics Research Unit, Faculty of Information Technology and Electrical Engineering, University of Oulu,
2 Ministry-province jointly-constructed cultivation base for state key laboratory of processing for non-ferrous metal and featured materials, Key laboratory of new processing technology for non-ferrous metal and materials ministry of education, College of Materials Science and Engineering, Guilin University of Technology, 541004 Guilin, P.R. China
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Received in final form: 12 October 2018
Published online: 23 August 2019
Ba(Ni0.5Nb0.5)O2.75 (BNNO) doped KNbO3 (KN) and (K0.5Na0.5)NbO3 (KNN), abbreviated as KBNNO and KNBNNO, respectively, have been recently reported to co-exhibit narrow band gaps (visible range) and strong piezoelectric/pyroelectric effects simultaneously within the same material. This had never been achieved in a single ceramic material. Such a breakthrough may allure the development of fundamentally novel multi-source energy harvesters based on only one piece of material as well as advanced optoelectronic devices with multiple functions. It has been found that the window of getting the unique combination of these properties is very narrow. Even a slight shifting away from the stoichiometry of the compositions may induce a significant loss of the properties. The reasons are expected to be in the compositions and microstructure of these materials. However, detailed information – e.g. the correlation of the compositions, processing conditions, microstructure and properties – remains to be investigated for such novel materials. In this paper, the inter-influence of different doping amounts of BNNO, calcination and sintering temperatures, phase structures and defects (potassium loss and oxygen vacancy) on the dielectric and ferroelectric properties are studied. The paper reveals the principles and provides guidance to achieving good ferroelectric properties in these emerging perovskite structured materials.
© The Author(s) 2019
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Open access funding provided by the University of Oulu, Finland.