Structural, thermoelectric and magnetic properties of La-doped CaMnO3: Role of electron doping and mixed-valence effects
Journal of Alloys and Compounds, cilt.1076, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 1076
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.jallcom.2026.189403
- Dergi Adı: Journal of Alloys and Compounds
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, INSPEC, Public Affairs Index, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Anahtar Kelimeler: Electrical resistivity, Electron-doped CaMnO3, Magnetization, Seebeck coefficient, Thermoelectric oxides
- Çukurova Üniversitesi Adresli: Evet
Özet
The structural, microstructural, electrical, thermoelectric, and magnetic properties of La-doped Ca1-xLaxMnO3 samples with x = 0.00, 0.025, 0.05, 0.075, 0.10, 0.15, and 0.20 were systematically investigated to clarify the effect of A-site electron doping on n-type oxide thermoelectric performance. X-ray diffraction confirmed single-phase orthorhombic perovskite formation with lattice expansion upon La substitution. Field-emission scanning electron microscopy revealed progressive grain refinement, improved densification, and increased density with increasing La content. Electrical measurements showed a drastic reduction in resistivity and activation energy at low to moderate La levels, corresponding to enhanced carrier mobility via Mn3+-O-Mn4+ double-exchange interactions, while excessive doping induces charge-ordering and carrier localization. The Seebeck coefficient remains negative across all compositions, with the highest power factor achieved for x = 0.05. Magnetic characterization indicates a gradual decrease in Néel temperature and the emergence of ferromagnetic correlations with La doping, enhancing the magnetocaloric response. The results demonstrate that moderate La substitution optimizes the interplay between structural, electronic, and magnetic properties, highlighting the potential of Ca1-xLaxMnO3 as a stable and efficient high-temperature n-type thermoelectric material with multifunctional capabilities.