Spray-Deposited Rare Earth Metal Ions (La3+ and Sm3+) Substituted CoFe2O4 Thin Films for NH3 Gas-Sensing Applications

• Published in: Journal of superconductivity and novel magnetism 2022-09, Vol.35 (9), p.2563-2571
• Main Authors: Vadivel, M., Ramesh Babu, R., Sridharan, M.
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Condensed Matter Physics; Magnetic Materials; Magnetism; Original Paper; Physics; Physics and Astronomy; Strongly Correlated Systems; Superconductivity
• ISSN: 1557-1939; 1557-1947
• DOI: 10.1007/s10948-022-06309-2

We report here the NH 3 gas-sensing properties of homemade spray deposited pristine and different concentrations of La 3+ and Sm 3+ ions substituted CoFe 2 O 4 thin films. XRD findings reveal that the deposited pristine and metal ions substituted CoFe 2 O 4 thin films exhibit the single-phase cubic spinel structure. Also, the calculated average crystallite size was found to decrease from 21 to 17 nm and 21 to 14 nm for La 3+ and Sm 3+ -substituted CoFe 2 O 4 thin films, respectively. AFM topography images show a variation in surface morphology and roughness of CoFe 2 O 4 thin films by the substitution of La 3+ and Sm 3+ ions in the Fe 3+ site, thereby affecting the gas-sensing behavior of CoFe 2 O 4 thin films. Gas-sensing measurement demonstrates that the substitution of La 3+ and Sm 3+ ions in the CoFe 2 O 4 matrix significantly enhances the gas-sensing characteristics such as sensitivity, gas response, and recovery time of pristine CoFe 2 O 4 thin films. Hence, the experimental results obtained from the present study show that La 3+ and Sm 3+ -ion-substituted CoFe 2 O 4 thin films offer greater potential for the fabrication of room temperature NH 3 gas sensors even for low ppm concentrations.