https://doi.org/10.1007/s100510051070
Temperature dependence of infrared conductivity of manganites Pr0.7Ca0.3-xSrxMnO3 (x = 0, 0.05 and 0.2)
1
Laboratoire d'Électrodynamique des Matériaux AvancésLRC M01 associated to Commissariat à
l'Énergie Atomique, FRE 2077 associated to CNRS, Faculté des Sciences & Techniques, Université
François Rabelais, 37200 Tours, France
2
CRISMATUMR 6508, ISMRA, boulevard Maréchal Juin, 14050 Caen, France
Received:
20
July
1999
Revised:
15
October
1999
Published online: 15 April 2000
The temperature dependence of the reflectivity spectra of three manganites ceramics with compositions Pr0.7Ca0.3MnO3, Pr0.7Ca0.25Sr0.05MnO3 and Pr0.7Ca0.1Sr0.2MnO3 has been investigated by infrared reflectivity spectroscopy in the wave number range 0.005-1.1 eV. The compound Pr0.7Ca0.25Sr0.05MnO3 which shows the largest conductivity jump at the ferromagnetic-paramagnetic phase transition has been studied in details. The optical conductivity of this compound is deduced from the best fit to reflectivity spectra of a "double-damping Drude" model, itself derived from the factorized form of the dielectric function. Excellent agreement with Kramers-Kronig transformation is reported. The model allows in particular to discriminate the contributions to the optical conductivity of trapped charges (polarons) and mobile charge carriers.
PACS: 71.30.+h – Metal-insulator transitions and other electronic transitions / 75.70.Pa – Giant magnetoresistance / 78.30.-j – Infrared and Raman spectra
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000