Humidity-sensitive characteristic of Ba0.99La0.01SnO3

Samples of Ba0.99La0.01SnO3 (abbreviated name BSL01) have been synthesized by a solid-state ceramic route at 1200 C for 4 h. Synthesized powders have been characterized using techniques such as X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDXA). From XRD data, single-phase solid-solution formation has been confirmed. SEM of the sample exhibited a porous nature with small grain size in the range 0.2-0.4 μm. EDXA showed that the surface of the sample is barium deficient and oxygen rich. The distribution in pore size, average pore diameter and % porosity were obtained from the mercury-intrusion method. The average pore diameter and % porosity are 0.34 μm and 26, respectively. At room temperature the effect of humidity on conductance and capacitance in the frequency range 20 Hz-1 MHz and relative humidity (RH) range 10-95% have been measured. It is observed that frequency has more influence on capacitance as compared to resistance. The variation of conductivity with RH is linear whereas of the capacitance is nonlinear. The response and recovery times are 44 s and 56 s, respectively. The hygroscopic nature of the sample has been supported by Fourier transforms infrared (FTIR) and thermogravimetric analysis (TGA) data. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)