Journal Article

FZJ-2020-01697

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Defect chemistry of donor-doped BaTiO 3 with BaO-excess for reduction resistant PTCR thermistor applications – redox-behaviour

Pithan, C. (Corresponding author)FZJ* ; Katsu, H. ; Waser, R.FZJ*

2020
RSC Publ. Cambridge

This record in other databases:      

Please use a persistent id in citations: http://hdl.handle.net/2128/26076  doi:10.1039/C9CP06793K

Abstract: The electrical conductivity of donor-doped BaTiO3 thermistor ceramics with excessive BaO revealing a reduction-persistent PTCR effect has been carefully examined depending on materials’ composition and oxygen partial pressure at moderate temperatures between 973 and 1273 K. This thermal regime represents the range which is relevant for the realization of insulating grain boundaries in these electrically inhomogeneous ceramic materials through reoxidation. Based on the experimental results strong evidence for a general correlation between the PTCR characteristics, DC-conductivity and the herewith associated defect chemistry significant to thermistor applications is presented for the system (Ba, La)mTiO3, where m designates the BaO-excess (m ≥ 1). Nominal compositions with a relatively low (Ba + La)/Ti ratio m only show a rather poor PTCR effect and an overall donor-type response in conductivity can be observed at all levels of oxygen partial pressure considered in the present study. With increasing (Ba + La)/Ti ratio m the nonlinear resistivity jump with increasing temperature strongly improves and the acceptor-type behaviour seems to dominate the total conductivity at partial pressures of oxygen above approximately 10−6 MPa. This result for compositions with high BaO-excess can be understood by the local formation of point defect associates in the grain boundary regions that consist of both acceptor-type titanium vacancies and donor-type oxygen vacancies. Their origin is attributed to the preferential local incorporation of excessive BaO into the BaTiO3 lattice at the intergranular interfaces.

---

Contributing Institute(s):

1. Elektronische Materialien (PGI-7)
2. JARA-FIT (JARA-FIT)

Research Program(s):

1. 524 - Controlling Collective States (POF3-524) (POF3-524)

Appears in the scientific report 2020

---

Database coverage:
; ; Allianz-Lizenz / DFG ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; NCBI Molecular Biology Database ; National-Konsortium ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

---