Group of Mössbauer Spectroscopy

 

Head of group: Dr. Sc., Julia A.Fedotova

 

Basic area of research:

Ø     Nanostructured, nanocomposite materials

Ø     Intermetallic compounds

 

Main publications

1.     J.A.Fedotova et al. Effect of grain boundaries on iron distribution in policrystalline cubic boron nitride // J.Phys. C: Cond. Matter.- 2002.- 14, ¹ 48.- p. 12855-12864.

2.     J.A.Fedotova et al. Mössbauer study of iron impurities in cubic boron nitride // J. Alloys & Comp.- 2003.- V. 352.- p. 296-303.

3.     J.A.Fedotova et al. Charge states and distribution of iron ions in policrystalline cubic boron nitride // Optical materials.- 2003.- V. 23.- p. 71-77.

4.     A.M.Saad, A.V.Mazanik, Yu.E.Kalinin, J.A.Fedotova et al. Structure and electrical properties of CoFeZr-aluminium oxide nanocomposite films // Rev. Adv. Mater. Sci.- 2004.- V. 8.- p. 152-157.

5.     J.Fedotova et al. Atomic arrangement in B2 FeAl prepared by self-propagated high-temperature synthesis at varying Al content and annealing // Hyp. Int.- 2005.- V. 159.- p. 305-311.

6.     J. Fedotova et al. The effect of the sputtering process ambient on the magnetic state and phase composition of the film nanocomposites (Fe0.45Co0.45Zr0.10)x(Al2O3)1-x // Hyper. Inter.- 2005.- V. 165.- p. 127-134.

7.     J.Fedotova et al. 57Fe Mössbauer study of localization and valence state of iron ions in granular nanocomposites (FeCoZr)x(Al2O3)100-x for spintronic applications // Proc. Int. Symp. “Industrial application of the Mössbauer effect (Madrid, 4-8 October, 2004) AIP conference proceedings.-2005.- Vol. 765.- ð. 127-131.

8.     J. Fedotova et al. Phase and structural transformations in FexAl1-x powder alloys studied by 57Fe Mössbauer spectroscopy and XRD // Proc. Int. Symp. “Industrial application of the Mössbauer effect (Madrid, 4-8 October, 2004) AIP conference proceedings.-2005.- Vol. 765.- ð. 317-321.

9.     A.Saad, A.K.Fedotov, J.A.Fedotova et al. Characterization of (Fe0.45Co0.45Zr0.10)x(Al2O3)1-x nanocomposite films applicable as spintronic materials // Phys. Stat. Sol.- 2006.- V. C 3, ¹ 5.- 1283-1290.

10. A. Zaleski, J. Fedotova et al. Mossbauer, XRD and SEM study of FeAl-based powder alloys with nanoinclusions // Acta Physica Polonica.- 2006.- V. A 109, ¹ 3.- p. 441-444.

 

Main results

 

1.       Principles of diamond and cubic boron nitride (c-BN) defect structure behavior under thermobaric treatment were obtained as the result of investigation  concerning 57Fe ions localization and charge state in composite materials based on diamond and c-BN.  It was shown that low temperature treatment causes plastic (inelastic) deformation of composites, formation of low-angle grain boundaries and polygonization. Treatment temperature increase causes defect structure increase and grain boundaries disordering. The latter could be due to intense phase formation at the grain boundaries initiated by high temperature treatment. (State Program of Fundamental Investigations “Crystallophysics”, State Program of applied studies “Priborostroenie” (Instrument engineering), BRFFI project “Mossbauer Spectroscopy Investigation of iron-containing defect complexes in sfalerite boron nitride”)

2.       Influence of inert and chemically-active additions (Argon, Hydrogen, Oxygen) on percolation transitions in nanocomposites was determined using analysis of correlation between magnetic and electric properties on the one side and phase composition and structure of iron-containing nanoparticles in nanostructured composite materials on the other (State Complex Program of Applied Scientific Research “Nanotech”).

3.       Hyperfine interactions of iron ions in iron aluminide powder alloys obtained by Self-Propagated High-Temperature Synthesis (SHS) were investigated. Peculiarities of iron aluminides defect structure which originate from non-equilibrium synthesis process were determined (State Complex Program of Applied Scientific Research “Nanotech”).