Nanocrystalline spinel NixCu0.8-xZn0.2Fe2O4: a novel material for humidity sensing

The humidity sensing property of the ferrite systems Ni (x) Cu0.8-x Zn0.2Fe2O4 with 0.0 a parts per thousand currency sign x a parts per thousand currency sign 0.8 (x = 0, 0.2, 0.4, 0.6, 0.8) was studied using the standard ceramic technique. The spinel structure of the compounds was confirmed by X-ray diffraction studies, BET study and surface morphology by scanning electron microscopy. The compounds were subjected to dc electrical conductivity studies at room temperature. The resistance measurements as a function of relative humidity (RH) in the range of 5-98% were done and the humidity sensing factors (S (f) = R (5%)/R (95%)) were calculated. The composite NiCuZn-3 (x = 0.4) possessed the highest humidity sensing factor of 3051.9 +/- A 500, whilst CuZn-1 (x = 0) possessed the lowest humidity sensing factor of 45.3 +/- A 12. The other compounds possessed lower humidity sensing factors of 116.7 +/- A 35, 783.4 +/- A 160 and 416.2 +/- A 65 for x = 0.2, 0.6 and 0.8, respectively.