If you are experiencing problems downloading PDF or HTML fulltext, our helpdesk recommend clearing your browser cache and trying again. If you need help in clearing your cache, please click here . Still need help? Email help@ingentaconnect.com

New Negative Temperature Coefficient Ceramics in Ca–Ce–Nb–M–O (M=Mo or W) System

$48.00 plus tax (Refund Policy)

Download / Buy Article:


A series of quaternary powellites with varying cerium contents in a Ca–Ce–Nb–M–O (where M=Mo or W) system has been synthesized through the solid-state route. Powder X-ray diffraction analysis shows that these compounds crystallize in a tetragonal powellite structure with the I41/a space group. The structure was further confirmed by Raman spectroscopic analysis. The electrical conductivity studies reveal that they exhibit negative temperature coefficient (NTC) thermistor characteristics. The characteristic parameter of the thermistor () is found to be in the range of 5000–7000 K, and these values can be tuned with the cerium concentration. The electrical conductivity in these compounds is due to the presence of Ce3+, which remains in the reduced state without being oxidized to Ce4+ due to the structural stabilization. The X-ray photoelectron spectroscopy analysis corroborates the presence of Ce in the 3+ state.

Document Type: Research Article

DOI: http://dx.doi.org/10.1111/j.1551-2916.2010.03616.x

Affiliations: Materials and Minerals Division, National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum 695 019, Kerala, India

Publication date: June 1, 2010

Related content



Share Content

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more