Humidity response of Li-substituted magnesium ferrite

Humidity sensitivity of Mg1−xLixFe2O4 (0.0 ≤ x ≤ 0.6) samples prepared by solid-state reaction of inorganic precursors has been studied. Specimens prepared by this method were confirmed to exhibit spinel structure by X-ray diffraction studies and FT-IR spectral absorption peaks observed in mid IR spectroscopic analysis at υ1 = 580–600 cm−1 and υ2 = 400–436 cm−1. Distribution of nano-size grains was observed by scanning electron micrographs. It was observed that the grain size further decreased from 200 nm to 110 nm with substitution of lithium ions. The sensitivity factor increased from 165 for pure magnesium ferrite to 2080 for lithium substitution in the range 10–80% RH. The shortest response time was measured to be 180 s for the x = 0.4 composition sample.