Saha, Dipika and Das Sharma, Abhijit and Sen, Amarnath and Maiti, Himadri Sekhar (2002) Preparation of bixbyite phase (MnxFe1-x)(2)O-3 for NTC thermistor applications. Materials Letters, 55 (6). pp. 403-406. ISSN 0167-577X

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Spine] compounds like doped Mn3O4 and ferrites are conventionally used as negative temperature coefficient (NTC) thermistors. Incidentally, Mn2O3 has got two orders of magnitude lower room temperature resistivity than that of Mn3O4 and it is expected that doped Mn2O3 should perform better than doped Mn3O4 as NTC thermistor. However, Mn2O3 can not be fabricated in the ceramic form as it decomposes to Mn3O4 above 900 degreesC. We have found that iron, as solid solution, can stabilize Mn2O3 as bixbyite (MnxFe1-x)(2)O-3 phase even at high temperatures We have successfully prepared phase-pure nano-size powders of (MnxFe1-x)2O3 (where x = 0.98, 0.66 and 0.37) by citrate-nitrate gel method. After sintering the precursor powders at high temperature (1500 degreesC), their electrical behaviour was studied. It has been found that the NTC sensitivity index (beta) of the bixbyite phase (MnxFe1-x)(2)O-3 (where x=0.37 and 0.66) can be as high as 6000 K (in the temperature range of 50-150 degreesC) which is appreciably higher than that of conventional NTC materials. (C) 2002 Elsevier Science B.V. All rights reserved.

Item Type: Article
Uncontrolled Keywords: NTC thermistor; Transition metal oxide; Bixbyite phase; Autoignition technique
Subjects: Electronics
Depositing User: Bidhan Chaudhuri
Date Deposited: 22 Mar 2012 12:32
Last Modified: 22 Mar 2012 12:32

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