Hydrogen sensing characteristics of nano-crystalline Mg0.5Zn0.5Fe2O4 thin film: Effect of film thickness and operating temperature

• Mg0.5Zn0.5Fe2O4 thin films are deposited by spin coating the sol on alumina.
• Phase, microstructure and hydrogen sensing features of the films are investigated.
• Prepared films are promising for chemi-resistive type detection of hydrogen.
• Non-conventional Mg0.5Zn0.5Fe2O4 films can detect 20 ppm hydrogen at 250 °C.
• Sensing characteristics are found even superior than few conventional sensors.

To yield stable base resistance and reproducible sensing characteristics, thin film based sensors are considered superior than particulate Taguchi type sensor. The sensing characteristics of ferrite based thin film sensor have hardly been reported in literature. In the present work, the hydrogen sensing characteristics of magnesium zinc ferrite thin film sensor is reported by varying the film thickness, test gas concentration and sensor operating temperature. These thin films were deposited on alumina substrate by sol–gel spin coating route. X-ray diffraction analyses and electron microscopy images of the thin film confirm the nano-crystalline nature of these films. It is reported that the film thickness plays a major role to control the gas sensing characteristics of the deposited films.