Significant increase in humidity sensing characteristics of praseodymium doped magnesium ferrite

Magnesium ferrite has been doped by Pr in 0.1 mol% and 0.3 mol% concentration for enhancing humidity sensing properties. The spin density/dangling bond calculated by electron paramagnetic resonance (EPR) increased from 8.15 × 1020 to 15.6 × 1020 for 0.3 mol% Pr doped compared to undoped magnesium ferrite sample. The bulk porosity of the samples in this case increases from 8.4% to 34% with Pr doping. Pr doping increased the sensitivity factor Z10%/Z90% from 24 to 113. Impedance gradient |dlog Z/dRH| at low 10–30% RH and high 70–90% RH has been determined with respect to spin density and porosity for the samples. A maximum drift in humidity hysteresis of 22% RH is predominantly reduced to 2% RH by a 0.1 mol% Pr doping in magnesium ferrite. Such remarkable improvements identified this material as a strong candidate for humidity sensors.