Colossal humidoresistance in ceria added magnesium ferrite thin film by pulsed laser deposition

Abstract

Giant magnetoresistance (GMR) in multilayer thin films by applying an external magnetic field brought a breakthrough in the area of magnetic read heads. A colossal change in resistance has been observed in thin films by exposing it in humidity present in atmosphere. This effect can be best exploited for new type of energy conservative colossal humidoresistance (CHR) based device besides its established humidity sensor application. Here we report a colossal change in resistance of ceria added magnesium ferrite thin film prepared by pulsed laser deposition. A seven order (∼107) decrease in resistance has been observed for such film. The humidoresistance [R(0% RH)−R(95% RH)]/R(95% RH) measured 3×106 for 1wt.% ceria added magnesium ferrite film. The confirmation of physisorption of water molecules responsible for ionic conduction on film surface has been confirmed by impedance response of thin films with frequency at different humidity.