The microstructural and the magnetotransport properties of La 0.7 Ca 0.3 MnO 3 and La 0.7 Sr 0.3 MnO 3 films, deposited on a BaTiO 3 layer ͑LCMO/BTO and LSMO/BTO, respectively͒, and on LaAlO 3 and SrTiO 3 ͑001͒ single crystals ͑LCMO/LAO, LSMO/LAO and LSMO/STO͒ by rf-magnetron sputtering using the "soft" ͑or powder͒ targets, have been investigated. The films grown on BTO demonstrate biaxial tensile in-plane and compressive out-of-plane strains, while those grown on LAO show the opposite trend, i.e., compressive in-plane and tensile out-of-plane strains. The films with a biaxial tensile in-plane strain undergo the magnetic transition at a higher temperature than those with a biaxial compressive one. This implies that the variation of Mn-O-Mn bond angle, controlled by the lattice strain, plays a more important role in the formation of spin ordering in the manganite film than the modification in the Mn-O bond length does. It was shown that the magnetic inhomogeneity, observed through the difference between field-cooled and zero-field-cooled temperature-dependent magnetization, is not greatly relevant to the electronic nature, but is controlled by the lattice distortion and the microstructural defects. The observed enhancement of magnetoresistance for the LSMO/BTO bilayer at room temperature makes this material system promising in the development of new hybrid ferromagnetic/ferroelectric devices.

The resistivity of Pr0.65 Ca0.35 MnO3 films prepared by pulsed laser deposition has been measured in the temperature range 4.2 - 300 K. The formation of metallic phase is suggested by the analysis of the temperature dependence of resistivity at low temperatures under zero-magnetic field. It is shown that the appearance of the charge-ordered state at 205 K can be controlled by the lattice strains accumulated during the film growth. The charge-ordering energy gap was estimated to be 77.5 meV from the experimental data. Experimental results are interpreted on the basis of the phase-separation model.

The mixed-state superconducting properties of bulk MgB2+2 at.%TiO2, prepared by the in situ solid state reaction, have been investigated. The high-resolution transmission electron microscopy study reveals that the sample has combined microstructures, consisting of regions with small- and large-size MgB2 grains, and the MgO inclusions. The particular grains are separated by thin TiB2 interlayers along the c axis. Analysis on the mixed-state parameters, such as the upper critical field, the coherence length and the Ginzburg–Landau parameter κ, proves that the MgB2+2 at.% TiO2 belongs to a high-κ type-II superconductor in the dirty limit. The non-uniformly scaled microstructure results in an unusual (close to the double peak) magnetic field dependence of the pinning force density. The field-cooled temperature dependence of magnetic moment exhibits a transition of the sample to the paramagnetic state at certain applied magnetic fields, which is treated as a manifestation of the paramagnetic Meissner effect. The experimental results are discussed on the basis of modern theoretical approaches.

The effects of lattice strain on the magnetic and the transport properties of La0.8Sr0.2MnO3 films grown on an (001) LaAlO3 substrate and on a La0.8Ca0.2MnO3 layer have been studied. It was observed that the metal-insulator and the ferromagnetic transitions turn out to be at higher temperatures for the film deposited on La0.8Ca0.2MnO3 layer with respect to that on LaAlO3. The dependence of Curie temperature on the bulk and the Jahn–Teller strains has also been determined.