Thermistor behaviour and electric conduction analysis of Ni-doped niobate ferroelectric: the role of multiple beta parameters

Author(s)

Lanfredi, Silvania ^[1] ; Palacio, Gustavo ^[2] ; Bellucci, Felipe S. ^[3] ; Colin, Claire V. ^{[4, 5]} ; Nobre, Marcos A. L. ^[1]

Affiliation

^[1] Univ Estadual Paulista UNESP, FCT, BR-19060900 Presidente Prudente, SP - Brazil

^[2] Univ Estadual Paulista UNESP, Inst Biociencias Letras & Ciencias Exatas, Sao Jose Do Rio Preto, SP - Brazil

^[3] Univ Estadual Paulista UNESP, Fac Ciencias FC, BR-17033360 Bauru, SP - Brazil

^[4] CNRS, Inst Neel, F-38042 Grenoble 9 - France

^[5] Univ Grenoble 1, F-38042 Grenoble 9 - France

• Document type: Journal article
• Source: JOURNAL OF PHYSICS D-APPLIED PHYSICS; v. 45, n. 43 OCT 31 2012.
• Web of Science Citations: 13

Abstract

A new engineered non-stoichiometric niobate ceramic with a tetragonal tungsten bronze (TTB)-type structure is prepared by non-isovalent substitution at the niobium backbone. The compound's formula is KSr2(Ni0.75Nb4.25)O-15 (delta), with space group equal to P4bm (\#100), a polar group. Electrical properties of this new ferroelectric-semiconductor ceramic are investigated by impedance spectroscopy in the temperature range from 453 up to 953 K. The curve of the resistance as a function of temperature presents further characteristics of a temperature sensor with a negative temperature coefficient (NTC). At high temperatures, the analysis of electrical parameters shows an NTC behaviour ceramic with three distinct thermistor characteristic parameters, beta. The values of the beta parameter change from 9.82 x 10(3) to 1.29 x 10(4) K, while the temperature coefficient of resistance a changes from -0.047 to -0.023K(-1). The NTC behaviour of KSr2(Ni0.75Nb4.25)O15-delta is compared with the behaviour of some dielectric and other ferroelectric semiconductors. beta dependence with dc or the ac conductivity mechanism and its correlation with beta quality are discussed. (AU)

• FAPESP's process: 07/03510-9 - Structural characterization of nanopowders of semiconductor ferroelectric oxides
• Grantee: Silvania Lanfredi
• Support Opportunities: Regular Research Grants