IR absorption of trapped and free Jahn-Teller polarons in 3D-crystals and films of LaMnO3 and La2/3Sr1/3MnO3
Autor(en): | Wierschem, M Kapphan, S Vikhnin, VS |
Stichwörter: | charge transfer vibronic exciton; IR-absorption; Jahn-Teller polaron; MANGANITES; Materials Science; Materials Science, Multidisciplinary; perovskites; Physics; Physics, Condensed Matter | Erscheinungsdatum: | 2004 | Herausgeber: | TAYLOR & FRANCIS LTD | Journal: | FERROELECTRICS | Volumen: | 299 | Startseite: | 49 | Seitenende: | 54 | Zusammenfassung: | The experimental and theoretical study of IR-absorption in LaMnO3 (LMO) single crystals has led to the observation of new five well-defined peaks. Their positions at RT are the following: 0.161 eV, 0.147 eV, 0.130 eV, 0.117 eV, and a much more broadened peak at similar to0.24 eV. The IR-absorption and its temperature and heat treatment dependence was studied with the help of a Fourier IR spectrometer Bruker IFS 120 HR. Analogous peaks of IR-absorption in LMO films are shifted to the lower energy side. The La-2/3 Sr-1/3 MnO3 film IR-absorption is characterized by additional broadening. The results were interpreted as direct detection of Jahn-Teller hole free polarons, as well as trapped hole and electronic polarons in LMO and related systems. Two type of Jahn-Teller hole states were used in this model. There were free Jahn-Teller hole polarons, and Jahn-Teller hole polarons within localized charge transfer vibronic excitons (Mn4+-Mn2+ pairs). IR-absorption peak induced by electronic polaron within such type exciton mentioned above was also interpreted. |
Beschreibung: | 3rd International Seminar on Relaxor Ferroelectrics (ISRF 3), Dubna, RUSSIA, JUN 14-17, 2000 |
ISSN: | 00150193 | DOI: | 10.1080/00150190490428700 |
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geprüft am 18.05.2024