LPG gas sensing and humidity sensing studies of gamma irradiated Co_0.5Ni_0.5Ce_0.01Fe_1.99O₄ nanocomposite thin film for sensor application

The solution combustion synthesis approach was successfully used to produce rare-earth (RE) Cerium (Ce³⁺)-substituted Co–Ni ferrite nanoparticles having the formula Co_0.5 Ni_0.5 Ce_0.01 Fe_1.99 O₄. The synthesized nanoparticles were irradiated using ⁶⁰Co γ rays for 50 kGy and 100 kGy. The lattice parameter decreases with the irradiation dosage. The gas sensing responses of irradiated thin films at an ambient temperature were examined. Thin film of the sample irradiated at 100 kGy shows maximum sensing response for methane gas. The sensing responses and recovery times were recorded. According to the stability investigation, the sensing response of 100 kGy thin film was extremely stable after 60 days of exposure to methane (1000 PPB). Due to its high sensitivity, short reaction and recovery times, and stability, the sample thin film with 100 kGy irradiation can be used in gas sensor technology, particularly for the detection of methane gas at room temperature. The humidity sensing studies initiated by recording the variation of resistance, capacitance, response and recovery times were recorded. The humidity hysteresis loss and stability studies were carried out. A negligible loss in sensing response was noticed.