EPR studies of some ferrates and their correlation with humidity sensitivity

Puneet Misra; Rajesh Kumar Shukla; L. M. Bali; C. L. Gupta; G. C. Dubey

doi:10.1117/12.514849

14 October 2003 EPR studies of some ferrates and their correlation with humidity sensitivity

Puneet Misra, Rajesh Kumar Shukla, L. M. Bali, C. L. Gupta, G. C. Dubey

Proceedings Volume 5062, Smart Materials, Structures, and Systems; (2003) https://doi.org/10.1117/12.514849
Event: Smart Materials, Structures, and Systems, 2002, Bangalore, India

Abstract

Various oxides have been reported to be sensitive to humidity of the environment. Recently ceramic type humidity sensors using aluminates and ferrates are widely reported as stable sensors. The change in electrical resistance due to change in humidity is considered due to adsorption of water molecule in the pores of material. If the material has more active centers, it will yield better results. It is suggested that the protonic conduction is possible due to pores where H₃O⁺ and OH^- ions are formed due to moisture adsorption. The formations of protonic ions are possible if electrically active centers are present which will help to increase the sensitivity. It ^αis expected that in porous structure/surface the presence of dangling bonds may act as electrically active centers and facilitate the increase in sensitivity of the humidity sensor. The present paper reports the measurement of spin density of ferrates fired at different temperatures and correlates its humidity sensitivity with spin density. This explains that dangling bonds act as active centers and if the process of fabrication of humidity sensor increases the dangling bonds, it is possible to increase the sensitivity of the sensor.

Citation Download Citation

Puneet Misra, Rajesh Kumar Shukla, L. M. Bali, C. L. Gupta, and G. C. Dubey "EPR studies of some ferrates and their correlation with humidity sensitivity", Proc. SPIE 5062, Smart Materials, Structures, and Systems, (14 October 2003); https://doi.org/10.1117/12.514849

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