Terahertz–infrared electrodynamics of overdoped manganites La1–xCaxMnO3
| Autor: | Tao Zhang, Vasily Moshnyaga, Victor I. Torgashev, Reinhard K. Kremer, Stanislav Kamba, L. S. Kadyrov, Gabriele Untereiner, Martin Dressel, Boris Gorshunov, Sina Zapf, Elena S. Zhukova, Anatoly S. Prokhorov, Jan Pokorný, Florian Fischgrabe, Elizaveta Motovilova, Uwe S. Pracht |
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| Rok vydání: | 2014 |
| Předmět: |
Physics
Condensed matter physics Infrared Terahertz radiation Van Hove singularity 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences 3. Good health Brillouin zone Paramagnetism symbols.namesake Absorption band 0103 physical sciences symbols Antiferromagnetism General Materials Science 010306 general physics 0210 nano-technology Raman spectroscopy Instrumentation |
| Zdroj: | Phase Transitions. 87:1050-1059 |
| ISSN: | 1029-0338 0141-1594 |
| DOI: | 10.1080/01411594.2014.953508 |
| Popis: | We have measured low-temperature terahertz and infrared spectra of La1–xCa xMnO3 with x = 0.5; 0.6; 2/3, 0.7; 3/4, 0.85; 0.9; 0.95; 0.98 and x = 1 in the form of ceramics and epitaxial films. In the charge-ordered state for commensurate dopings (x = 2/3 and 3/4), we observed an absorption band at frequencies corresponding to the position of the lowest energy van Hove singularity in the folded Brillouin zone. The band is assigned to the boson peak. We observed qualitatively the same boson peak in Raman spectra of La1/3Ca2/3MnO3 ceramics. In antiferromagnetic phase, for the 0.5 ≤ x < 0.85 range of doping, the conductivity mechanism gradually changes from a hopping-like transport at low temperatures to the Drude behavior at elevated temperatures in the paramagnetic phase. For 0.85 ≤ x < 1 (canted antiferromagnetic phase), the electrons behave as Drude-like carriers in the whole temperature interval 5–300 K. |
| Databáze: | OpenAIRE |
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