Structural and electrical properties of titanium-doped yttrium niobate

• Published in: Journal of alloys and compounds Vol. 767; pp. 1186 - 1195
• Main Authors: Winiarz, P., Mielewczyk-Gryń, A., Wachowski, S., Jasiński, P., Witkowska, A., Gazda, M.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 30.10.2018; Elsevier BV
• Subjects: Carrier density; Clustering; Current carriers; Defect fluorite structure; Diffraction; Electrical properties; Electrical resistivity; Electrochemical impedance spectroscopy; Electronics; Heat conductivity; Ionic conductivity; Niobium; Oxygen ions; Protonic conductivity; Scanning electron microscopy; Titanium; Transmission electron microscopy; Vacancies; X ray photoelectron spectroscopy; X ray spectra; X-ray diffraction; Yttrium; Yttrium niobate; Yttrium niobate; Protonic conductivity; Defect fluorite structure; Ionic conductivity
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2018.07.134

In this work, the influence of the substitution of niobium by titanium in Y3Nb1-xTixO7-δ on the structural and electrical properties is reported. Several experimental techniques, i.e. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), X-Ray Photoelectron Spectroscopy (XPS) and Electrochemical Impedance Spectroscopy (EIS), were applied to investigate the system Y3Nb1-xTixO7-δ. Titanium in Y3Nb1-xTixO7-δ is an acceptor-type dopant which charge is mainly compensated by oxygen vacancies, moreover, it may adopt different valence states, therefore, oxygen ion-, proton- and electronic-type conductivity are expected. Very interesting, non-monotonic changes in electrical and structural properties as a function of titanium content were observed. The competition between the increasing charge carrier concentration and structural phenomena such as short-range pyrochlore ordering and/or vacancy clustering was proposed as responsible for this non-monotonicity. •Oxygen vacancies compensate titanium effective charge in yttrium niobate.•Protonic and oxygen ion conductivity is observed.•Titanium content affects properties of yttrium niobate in a non-monotonic way.