Iranian Journal of Materials Science and Engineering

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In present work Ni_0.7Cd_0.3Nd_xFe_2-xO₄ ferrite samples (0≤x≤0.03) were prepared by using oxalate co-precipitation technique. The different characterization techniques were achieved using X-ray diffraction (XRD), FT-infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), DC electrical resistivity and dielectric measurements. The crystallographic parameters such as crystal structure, crystallite size, lattice constant, unit cell volume and theoretical density have been systematically analysed. The XRD and FT-IR measurements confirmed the formation of single phase spinel ferrite structure. The cation distribution among the octahedral and tetrahedral sites has been proposed on the basis of analysis of XRD patterns by employing Rietveld refinement analysis. The samples exist as a mixed type spinel with cubic structure. The DC electrical resistivity confirms the semiconducting behaviour and the Curie temperature decreases with increase in Nd³⁺ content. The dielectric constant and loss tangent decreases with frequency and higher frequencies remain constant, which shows the usual dielectric dispersion due to space charge polarization. The AC conductivity reveals that the small type polarons responsible for conduction process.

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This study investigates the effect of SnO₂ as an additive on the structural, electrical, optical, and gas sensing properties of LaCrO₃ nanoparticles.  SnO₂ is added into the LaCrO₃ by weight percentage (1 wt. %, 3 wt. %, 5 wt. %, 7 wt. %, 9 wt. % and 11 wt. %) employing screen printing method. Initially, the nanoparticles of SnO₂ and LaCrO₃ separately synthesis by sol-gel method and then used for the development of thick films. LaCrO₃ is used as host material while SnO₂ is additive material. The structural characterizations like FESEM, EDX and XRD were carried out to investigate the morphology, elements and crystallite size respectively. The inclusion of SnO₂ modifies the crystalline structure and surface morphology of LaCrO_3, as revealed by structural analyses. The optical characterizations like FTIR and UV were used for the study of impact of SnO₂ additive on functional group and band gap of the host material respectively. Optical studies indicate a modification in the bandgap, affecting light absorption properties and indicating changes in electronic transitions. The electrical characterizations were conducted by using half bridge method. Electrical resistivity measurements show enhanced performance, likely due to variation in charge carrier mobility induced by the SnO₂ additive. Among other selected wt. % SnO₂ additives, 9 wt. % SnO₂ added LaCrO₃ thick films shows maximum sensitivity to CH₄ gas at 120^oC operating temperature. The gas sensing characteristics demonstrate enhanced sensitivity, selectivity, and response time to target gases, suggesting that SnO₂ doping improves the sensing capabilities of LaCrO₃ nanoparticles, making them more efficient as a gas sensor. Obtained findings suggest that, SnO₂ as an additive enhances the multifunctional properties of LaCrO₃ nanoparticles, making them promising candidates for advanced gas sensing applications.