Magnetotransport properties of the Pr0.5Ca0.5MnO3/La0.7Sr0.3MnO3 bilayer and the Pr0.5Ca0.5MnO3 and La0.7Sr0.3MnO3 films deposited on LaAlO3 (001) substrate by pulse laser deposition were investigated. X-ray diffraction and high-resolution electron-microscopy analysis reveal that lattice parameters for the constituent sublayers in the bilayer are very close to those for the individual films. It was found that a ferromagnetic transition in the La0.7Sr0.3MnO3 sublayer significantly modifies magnetotransport properties of the Pr0.5Ca0.5MnO3 constituent sublayer due to the magnetic proximity effect. Evidence of this effect includes the appearance of exchange bias interaction between the constituent sublayers, a localized-to-itinerant crossover in the system of polarized electrons, which results in formation of the Griffiths-like ferromagnetic state, and an unusual polar transport of carriers. Experimental results were analyzed within the framework of the modern theoretical approac@en

-ray diffraction analysis and high-resolution electron microscopy of BiFeO(3) films prepared by dc magnetron sputtering on single-crystal LaAlO(3) (001) substrates reveal that the films have a highly c-oriented orthorhombic crystalline structure. The magnetic properties of the BiFeO3 films are typical of ensembles of interacting superparamagnetic clusters, rather than Dzyaloshinskii-Moriya weak ferromagnets. The appearance of extrinsic nanoscale superparamagnetic clusters is explained by an oxygen deficiency in certain regions of the film, where ferromagnetic ordering can be realized through a double-exchange Zener mechanism.@en

Nd(0.52)Sr(0.48)MnO(3) films of various thicknesses have been prepared by dc magnetron sputtering on single crystal LaAlO(3) (001) substrates. Reducing the film thickness leads to a significant suppression of ferromagnetic (FM) ordering and the Curie point falls below the antiferromagnetic (AFM) transition temperature. When this occurs, a huge rise of the magnetoresistance ratio from 400 to 60 000% is observed in an applied magnetic field of 5 T. We surmise that this new kind of the enhanced colossal magnetoresistance effect originates in the FM/AFM competition and the collapse of the charge-ordered state at high magnetic fields, rather than in the regular double-exchange mechanism.@en