Microstructures and the corresponding magnetic properties of half-doped Nd0.5 Sr0.5 MnO3 films

The microstructural and magnetic properties of amorphous, nanoclustered, and self-organized bilayer Nd0.5 Sr0.5 MnO3 films, prepared by rf magnetron sputtering, are investigated. The amorphous film was found to be a typical paramagnet with free motion of the individual Mn spins, and the magnetic properties are well described on the basis of the Curie-Weiss approximation. The nanoclustered film manifests magnetic properties mimicking those of superparamagnetic particles following nonclassical magnetic dynamics. The self-organized bilayer film demonstrates a negative exchange bias typical of a ferromagnet/antiferromagnet hybrid system, in spite of the fact that both layers have a ferromagnetic origin. The magnetic properties of the films are discussed in detail on the basis of modern theoretical models.