Correlation between magneto-optical and transport properties of Sr doped manganite films.

Abstract The features of electronic structure of La 0.7 Sr 0.3 MnO 3, Pr 0.8 Sr 0.2 MnO 3 , and Pr 0.6 Sr 0.4 MnO 3 polycrystalline films of different thickness have been investigated using magnetic circular dichroism (MCD) in the range of 1.1–4.2 eV. The temperature behavior of the samples electrical resistance were also has been studied. It was found that films with high Sr content (0.3 and 0.4) act as high-temperature semiconductors, while the maximum in the temperature dependences of resistivity these films indicates the transition of the samples to the metallic state at some temperature T M-S , which is different for different sample thickness. The films with the lower Sr content (0.2) act as insulators in the used temperature range. The MCD spectra have been decomposed to the Gaussian-shaped lines, and the temperature dependence of intensity of each line has been analyzed in comparison with temperature dependence of the films magnetization and with their electric conductivity type. Different temperature behavior of the intensity of four specified Gaussian-lines was revealed for semiconductor films. In the case of insulating Pr 0.8 Sr 0.2 MnO 3 samples, the intensity of three specified Gaussian lines changes with the temperature in the same way as the magnetization changed. It was established that the lanthanide (La, Pr) type does not affect the MCD spectra shape for the films with the same electrical conductivity type. Besides, the correlation between the MCD data of the films and their conductivity type was revealed. Due to the detailed analysis of the specified Gaussian lines with taking into account the well-known in the literature absorption bands, lying outside the studied spectral region, the MCD bands for the studied manganite films have been identified with electronic transitions of a different nature. Highlights • La 0.7 Sr 0.3 MnO 3, Pr 0.8 Sr 0.2 MnO 3 , and Pr 0.6 Sr 0.4 MnO 3 films act as objects of research. • Magnetic circular dichroism (MCD) and electrical resistance of the films are studied. • Lanthanide type does not affect the MCD spectra shape for the films with the same electrical conductivity type. • MCD band of the positive sign near 2.3–2.4 eV is typical for the metallic films only. • Revealed MCD bands are identified with electronic transitions of a different nature. [ABSTRACT FROM AUTHOR]