Infrared studies of a La0.67Ca0.33MnO3 single crystal: Optical magnetoconductivity in a half-metallic ferromagnet
01 January 1999
The infrared reflectivity of a La0.67Ca0.33MnO3 single crystal is studied over a broad range of temperatures (78-340 K), magnetic fields (0-16 T), and wave numbers (20-9000 cm(-1)). The optical conductivity gradually changes from a Drude-like behavior to a broad peak feature near 5000 cm(-1) in the ferromagnetic state below the Curie temperature T-C= 307 K. Various features of the optical conductivity bear striking resemblance to recent theoretical predictions based on the interplay between the double exchange interaction and the Jahn-Teller electron-phonon coupling. A large optical magnetoconductivity is observed near T-C. {[}S0163-1829(99)50602-4].