Peculiarities of magneto-infrared reflectivity of nanostructured manganite films

Abstract

Abstract The electrical resistance and reflectance of unpolarized infrared radiation have been studied in the La2/3Ba1/3MnO3 films with and without a variant structure. Applying of an external magnetic field leads to appearance of magnetoreflection and colossal magnetoresistance effects with maxima near the Curie temperature of the films. The high-angle boundaries markedly enhance the electric and magnetooptical properties of nanostructured epitaxial films with the variant structure. For example, an additional low-temperature contribution to the magnetoreflection has been revealed in La2/3Ba1/3MnO3/ZrO2(Y2O3) films. This peculiarity is associated with the change of the high-frequency conductivity of the films with the variant structure due to the processes of tunnelling of spin-polarized electrons across the boundaries of structural domains far below the Curie temperature of the sample. The detection of “tunnel magnetoreflection” in the doped lanthanum manganite films could promote extension of the scope of their application in the modern optoelectronics.