abstract
0.5Ba(Ti0.8Zr0.2)O-3-0.5(Ba0.7Ca0.3)TiO3 [50BZT-50BCT or BCZT] based compounds have been the focus of a lot of research, particularly motivated by their high piezoelectric effect. However, the literature lacks an elaborate investigation of the phase transition behavior in BCZT ceramics obtained by wet chemistry processing. Here, we present an in-depth study on the temperature dependence of x-ray diffraction (XRD), Raman scattering, dielectric properties, local piezoresponse and photoluminescence (PL) to investigate the sequence of phase transitions in the BCZT ceramic synthesized via a chemical route. Phase formation was determined by Rietveld analysis of XRD data, while compositional homogeneity and elemental quantification of the compound was validated using energy dispersive x-ray spectroscopy (EDX) and x-ray photoelectron spectroscopy (XPS) studies. Detailed fitting of XPS data indicated the existence of Ti3+ species (similar to 6%) in the prepared BCZT. Phase transitions were examined by analyzing the modifications in the XRD profile of Bragg reflection {200} and anomalies observed in the temperature variation of dielectric and Raman spectra studied over a wide temperature range starting from 10K to beyond Curie temperature. Crystallographic transformation temperatures obtained from dielectric measurement agreed well with those assessed from the temperature evolution of Raman spectra. In addition to other transitions, Raman scattering results revealed the existence of a transition from R3c to R3m phase near -175 degrees C, a transition that has not been interpreted in BCZT (and generally not observed in parent BaTiO3 compound). The luminescence response was studied by photoluminescence (PL) spectroscopy in the temperature range 15-300 K. The position of the PL peak was observed to shift with temperature and discontinuities in the wavelength shift were noted near phase transitions. Evolution of domain morphology with temperature was examined by piezoresponse force microscopy technique. Consolidated results assign the phase sequence in sol-gel derived BCZT as: R (R3c) ->(-175 +/- 10 degrees C) R (R3m) ->(-50 +/- 10 degrees C) O ->(40 +/- 10 degrees C) T ->(120 +/- 10 degrees C) C.
keywords
BARIUM-TITANATE; ELECTRICAL-PROPERTIES; PIEZOELECTRIC PROPERTIES; TRIGLYCINE SULFATE; PHASE-TRANSITION; GRAIN-SIZE; BATIO3; XPS; SPECTROSCOPY; PEROVSKITE
subject category
Materials Science
authors
Coondoo, I; Krylov, A; Sharma, DK; Krylova, S; Alikin, D; Kumar, JS; Mirzorakhimov, A; Melnikova, N; Soares, MJ; Kholkin, AL
our authors
Groups
G2 - Photonic, Electronic and Magnetic Materials
G3 - Electrochemical Materials, Interfaces and Coatings
Projects
Collaboratory for Emerging Technologies, CoLab (EMERGING TECHNOLOGIES)
acknowledgements
I.C. and J.S.K would like to acknowledge financial assistance by national funds (OE) , through FCT - Fundacao para a Ciencia e a Tec-nologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, financed by na-tional funds through the FCT/MCTES. This work was partially devel-oped within the scope of the project i3N, UIDB/50025/2020 & UIDP/50025/2020, financed by national funds through the FCT/MEC. Part of this work (A.K.) was supported by the Ministry of Science and Higher Education of the Russian Federation (grant no. 075-15-2021-588) . This research used resources of the Ural Center for Shared Use Modern nanotechnology, Ural federal University, Russia and the Krasnoyarsk Regional Center of Research Equipment of Federal Research Center Krasnoyarsk Science Center SB RAS. The authors thank Dr. Gonzalo Irurueta, Center for Mechanical Engineering and Automation, Univer-sity of Aveiro, Portugal and Dr. E. Venkata Ramana, Department of Physics, University of Aveiro, Portugal.