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<p>Polycrystalline CaMn<sub>1−x</sub>Ti<sub>x</sub>O<sub>3</sub> (0 ≤ x ≤ 0.08) perovskites were fabricated by making the use of standard traditional solid-state reaction route to study how Ti incorporation influences their structural, microstructural, optical, and dielectric properties. Across all samples, X-ray diffraction results indicated an orthorhombic perovskite phase, accompanied by a small lattice expansion caused by the incorporation of larger Ti⁴⁺ ions at Mn⁴⁺ sites. Crystallite size showed a non-linear variation, with grain refinement at lower doping levels and coarsening at higher concentrations, while dislocation density and lattice strain trends indicated maximum distortion at x = 0.02. SEM analysis revealed polyhedral grains with a systematic decrease in particle size upon Ti incorporation, consistent with inhibited grain boundary mobility. The X-ray Photoelectron Spectroscopy survey spectrum verifies the presence of Ca, Mn, Ti, and O elements in the prepared CaMn<sub>1−x</sub>TiₓO<sub>3</sub> sample. The investigated core-level peaks corresponding to Ca 2p, Mn 2p, Ti 2p, and O 1s validate the efficient doping of Ti into the CaMnO₃ lattice. From UV-Vis DRS measurements, pure CaMnO₃ was commence to obtain a direct band gap of 3.08&#xa0;eV, that reduced to 2.98&#xa0;eV at x = 0.08 as a consequence of Ti-O-Mn interactions and defect-induced tailing of the band edges. Dielectric measurements depicted higher permittivity and loss at low frequencies which diminished with increasing frequency that follows Maxwell-Wagner and Koop’s models. Cole-Cole analysis confirmed non-Debye relaxation associated with grain and grain boundary contributions. Overall, Ti substitution effectively tunes lattice structure, optical band gap, and dielectric response, making CaMnO₃-based ceramics promising candidates for electronic, microwave, and energy-related applications.</p>

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Impact of Ti substitution on optical properties and dielectric behaviour of perovskite CaMnO₃

  • 期刊论文

  • 发表日期：

    2026年7月6日

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  • Dhyani Parikh,
  • Krishna Chandra Roy,
  • C. R. Vaja,
  • Nisha Thankachen

摘要

Polycrystalline CaMn1−xTixO3 (0 ≤ x ≤ 0.08) perovskites were fabricated by making the use of standard traditional solid-state reaction route to study how Ti incorporation influences their structural, microstructural, optical, and dielectric properties. Across all samples, X-ray diffraction results indicated an orthorhombic perovskite phase, accompanied by a small lattice expansion caused by the incorporation of larger Ti⁴⁺ ions at Mn⁴⁺ sites. Crystallite size showed a non-linear variation, with grain refinement at lower doping levels and coarsening at higher concentrations, while dislocation density and lattice strain trends indicated maximum distortion at x = 0.02. SEM analysis revealed polyhedral grains with a systematic decrease in particle size upon Ti incorporation, consistent with inhibited grain boundary mobility. The X-ray Photoelectron Spectroscopy survey spectrum verifies the presence of Ca, Mn, Ti, and O elements in the prepared CaMn1−xTiₓO3 sample. The investigated core-level peaks corresponding to Ca 2p, Mn 2p, Ti 2p, and O 1s validate the efficient doping of Ti into the CaMnO₃ lattice. From UV-Vis DRS measurements, pure CaMnO₃ was commence to obtain a direct band gap of 3.08 eV, that reduced to 2.98 eV at x = 0.08 as a consequence of Ti-O-Mn interactions and defect-induced tailing of the band edges. Dielectric measurements depicted higher permittivity and loss at low frequencies which diminished with increasing frequency that follows Maxwell-Wagner and Koop’s models. Cole-Cole analysis confirmed non-Debye relaxation associated with grain and grain boundary contributions. Overall, Ti substitution effectively tunes lattice structure, optical band gap, and dielectric response, making CaMnO₃-based ceramics promising candidates for electronic, microwave, and energy-related applications.