Small polaron effect on carrier recombination in perovskite manganite thinfilms

Citation
Gr. Wu et al., Small polaron effect on carrier recombination in perovskite manganite thinfilms, SOL ST COMM, 118(8), 2001, pp. 419-424
Citations number
23
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
SOLID STATE COMMUNICATIONS
ISSN journal
0038-1098 → ACNP
Volume
118
Issue
8
Year of publication
2001
Pages
419 - 424
Database
ISI
SICI code
0038-1098(2001)118:8<419:SPEOCR>2.0.ZU;2-O
Abstract
Photoinduced 'transient thermoelectric effect (TTE)' in perovskite manganit e La0.6Ca0.4MnO3 thin film has been measured under magnetic fields. The fas t decay process of TTE signals is due to a recombination of photogenerated electron-hole pairs through Mn4+ ions as capture centers, whose evaluated c ross section sigma obeys the power law sigma proportional to T-1 (n = 0.75) in the ferromagnetic phase far below T-c and in the paramagnetic phase. Fr om the observed relaxation time tau (1), we evaluated the parameter ct char acterizing a small polaron effect and the effective mass m*; both are enhan ced appreciably near T-c. Such anomaly is attributed to the change in the t hermal velocity of diffusing holes with downspin due to a small polaron eff ect. (C) 2001 Published by Elsevier Science Ltd.