MgCl2 doped CuxZn1-xFe2O4 ferrite humidity sensors

The microstructure and humidity sensitivity of CuxZn1-xFe2O4 ferrites (where x varies from 0 to 1 mol% in steps of 0.2) doped with 0.05 and 0.1 wt% of magnesium chloride (MgCl2) prepared by standard ceramic route have been studied. X-ray diffraction (XRD) analysis indicates the formation of ferrite. Infrared (IR) transmission spectra show the presence of chlorine band, octahedral and tetrahedral group complexes. Scanning electron micrographs reveal the presence of granulation and pores, which play an important role in determining the humidity sensitivity. Microhardness, bulk density, porosity and water absorption properties were studied. It was found that the humidity sensitivity depends on composition and porosity. Dependence of electrical resistivity on composition, temperature and humidity was also investigated. Electrical resistivity decreases with the increase of temperature, humidity and molar weight of copper oxide (CuO) content. The resistivity of the 0.05 wt% MgCl2 doped CuxZn1-xFe2O4 ferrite is more dependent on humidity. The resistance humidity characteristics was examined. The good results concerning humidity sensitivity were obtained for 0.05 wt% MgCl2 doped ferrites except CuFe2O4 ferrite doped with 0.05 and 0.1 wt% MgCl2. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim