Magnesium‐Substituted Zinc Ferrite as a Promising Nanomaterial for the Development of Humidity Sensors

Abstract

Herein, the synthesis of zinc ferrite (ZnFe2O4) nanomaterials, substituted with magnesium (Mg), using the sol–gel autocombustion method, is reported. Powder X‐ray diffraction (PXRD), Fourier‐transform infrared (FTIR), field‐emission scanning electron microscopy (FESEM), and energy‐dispersive X‐ray spectroscopy (EDX) are used to characterize the synthesized Mg‐substituted ZnFe2O4. PXRD results show that unit cell volume and crystallite size decrease when the concentration of Mg ions rises. PXRD confirms that the nanomaterial has a single phase with the Fd3m space group. EDX confirms that the material is composed of Mg, Zn, Fe, and O elements. The FTIR spectra show a clear indication of the spinel ferrite structure, and the bands in the high‐frequency region reveal the hygroscopic nature of the prepared materials. The synthesized nanomaterial is used as a sensing element for the development of a humidity sensor. The average sensitivity (2.93 MΩ/%RH) is found to be highest for the composition Mg0.1Zn0.9Fe2O4. The response and recovery times of the fabricated thin‐film humidity sensor are 31 and 53 s, respectively. The developed sensing material has good repeatability (≈98%) and excellent stability.