Effect of A-site and B-site ion substitution on the electrical and thermoelectric properties of nanostructured perovskite CaMnO3

• Published in: Journal of materials science. Materials in electronics Vol. 35; no. 8; p. 600
• Main Authors: Mary, S. Berbeth, Mohan, K. S., Krishnan, M. Muthu
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-03-2024; Springer Nature B.V
• Subjects: Ambient temperature; Annealing; Carrier density; Characterization and Evaluation of Materials; Chemistry and Materials Science; Crystal structure; Differential thermal analysis; Electrical resistivity; Energy dispersive X ray analysis; Fourier transforms; Hydrothermal crystal growth; Infrared analysis; Infrared spectroscopy; Lattice parameters; Materials Science; Nanoparticles; Optical and Electronic Materials; Optical properties; Perovskite structure; Perovskites; Raman spectroscopy; Seebeck effect; Sol-gel processes; Spectroscopic analysis; Spectrum analysis; Substitutes; Temperature dependence; Thermoelectricity; Unit cell; X ray analysis; X ray powder diffraction
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-024-12351-8

The impact of A-site and B-site ion substitution (A-site: Sr and B-site: Co) on the electrical and thermoelectric properties of the perovskite CaMnO
3
nanoparticles has been investigated. The perovskite nanoparticles have been prepared by sol–gel hydrothermal method at 200 °C followed by annealing at optimum temperature.  Thermal, structural, morphological, elemental, functional, optical, electrical, and thermoelectric properties of the samples have been performed using TG-DTA analysis, powder X-ray Diffraction, Raman analysis, Scanning Electron Microscopy with Energy Dispersive X-ray Analysis, Fourier Transform Infrared Spectroscopy, UV–Vis spectroscopy, and thermoelectric measurement. Powder XRD analysis reveals the perovskite structure and the optimized annealing temperature. Surfactants reduced the average particle size which improves the thermopower. The decrease in substitution ionic size causes an increase in lattice parameters and unit cell volume. Oxygen-deficient nanoparticles were observed with symmetric Raman lines and the mesoporous structured nanoparticles enhanced the surface area leading to higher electrical conductivity. The temperature dependence thermoelectric measurement was performed between ambient temperature and 673 K. The electrical resistivity depends on the nature of substituent ions. The absolute Seebeck coefficient values for pure CaMnO
3,
A-site, and B-site substituted were − 312, − 287, and 98µVK
−1
, respectively. The systematic analysis revealed that ion substitution at the A-site and B-site influenced significant changes in the crystal structure and the type of carrier concentration.