New kind of humidity sensitive ceramic with linear property
Using the solid phase reaction method, La/sub 1-x/Sr/sub x/FeO/sub 3/ (0<or=x<or=1) ceramic was synthesized in an oxygen structure. Its resistance vs. relative humidity (RH) characteristics as well as the dielectric and complex impedance spectral characteristics were investigated. These results indicate that the resistance of LaFeO/sub 3/ decreases with RH, while the resistance of La/sub 1-x/Sr/sub x/FeO/sub 3/ (0.1<or=x<or=0.4) increases with increasing RH, and its sensitivity increases with the increasing x value. The equivalent circuit model of La/sub 1-x/Sr/sub x/FeO/sub 3/ has been established by complex impedance analysis, from which the conclusion can be drawn that the linear positive humidity sensitivity of the material is caused by the change in grain boundary resistance.<<ETX>>