Charge carrier localization in La1-xSrxMnO3 investigated by ac conductivity measurements

Citation
A. Seeger et al., Charge carrier localization in La1-xSrxMnO3 investigated by ac conductivity measurements, J PHYS-COND, 11(16), 1999, pp. 3273-3290
Citations number
57
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
JOURNAL OF PHYSICS-CONDENSED MATTER
ISSN journal
09538984 → ACNP
Volume
11
Issue
16
Year of publication
1999
Pages
3273 - 3290
Database
ISI
SICI code
0953-8984(19990426)11:16<3273:CCLILI>2.0.ZU;2-G
Abstract
We have investigated the complex ac conductivity of La1-xSrxMnO3 for 0 less than or equal to x less than or equal to 0.2, temperatures 15 K less than or equal to T less than or equal to 300 K and frequencies 20 Hz less than o r equal to nu less than or equal to 1.8 GHz. In addition, results from de m easurements are presented. From the frequency dependence of the complex con ductivity we find hopping of Anderson-localized charge carriers as the domi nant transport process in certain temperature and composition ranges. We de duce that, while Anderson localization is not the driving mechanism for the metal-insulator transition observed in this compound, it is responsible fo r the high-resistivity regions observed at low doping levels and low temper atures. The results indicate a polaronic nature of the charge carriers. Fro m the temperature dependence of the ac conductivity and the magnetic permea bility, deduced in the skin-effect-dominate regime, various phase transitio n temperatures have been determined.