Abstract
This paper reports the structural and electrical properties of negative temperature coefficient (NTC) of ceramics based on 0.6MgAl2O4-0.4La1−x Sr x CrO3 (x = 0–0.1). The X-ray diffraction analysis indicates that as-sintered composite ceramics consist of a cubic spinel MgAl2O4 phase and an orthorhombic perovskite La1−x Sr x CrO3 phase which is isomorphic to LaCrO3. In terms of SEM and EDS analyses the brighter regions are La1−x Sr x CrO3, and the darker regions are MgAl2O4. There is mutual diffusion and ion migration between two phases. X-ray photoelectron spectroscopy analysis corroborates the presence of Cr3+, Cr4+ ions on lattice sites, which result in hopping conduction. The resistivity decreases with the content of Sr2+ increasing. The values of ρ200 ,B200/500 and Ea of the as-sintered composite NTC thermistors are in the range of 203.81–4937.58 Ω cm, 2137.97–3506.01 K and 0.184–0.302 eV, respectively. The electrical properties of these ceramics can be adjusted by the Sr2+ contents.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
