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The paper reports on a comparative study of local Fe states, phase composition and magnetoresistivity of granular nanocomposite films FeCoZr–CaF 2 sintered in pure Ar and Ar + O sputtering atmosphere. For the first time peculiarities of temperature and magnetic field dependencies of magnetoresistance are analyzed with respect to partial oxidation of nanoparticles and perpendicular magnetic shape anisotropy.

Using Mossbauer Spectroscopy the kinetics of the σ-phase formation was studied in situ on Ti-doped quasi-equiatomic Fe–Cr alloys having an average grain size equal to 31(2) μm. The kinetics was studied both with a traditional approach i.e. the amount of the σ-phase precipitated, A σ , was determined from the spectral area, as well as with a novel approach i.e. in terms of the average isomer shift. In both cases the data could be well fitted in terms of the Johnson–Avrami–Mehl equation which yielded the kinetics parameters: the time constant, k , and the form factor, n . Assuming the k -values follow the Arrhenius law, the Ti-induced change in the activation energy, E , was determined. In particular, it was revealed that addition of 1.5 at% Ti or less accelerates the transformation, with the highest rate for 0.3 at% Ti, and the difference in E equals to 18.8 kJ/mol. In alloys with Ti-content higher than 1.5 at%, the formation of the σ-phase was retarded. The value of E =207±20 kJ/mol was found for the Fe 53.8 Cr 46.2 alloy.

The spin echo nuclear magnetic resonance spectra of Y 2 Co 17 A x (A≡N, C, H) are presented. On the basis of the satellite pattern of the 89 Y spectra, we have deduced that N and C atoms occupy the 9e sites (rhombohedral compounds) or 6h sites (hexagonal compounds) around the yttrium site. A decrease in the hyperfine fields at the yttrium and cobalt sites caused by neighbouring interstitial atoms is observed, with a magnitude dependent on the site and the type of interstitial atom. The effect is discussed in terms of the influence of N, C and H atoms on the local electronic structure at the yttrium and cobalt sites and compared with the effect observed in the RE 2 Fe 17 -based compounds (RE, rare earth).