National University of Science and Technology MISIS:

V. G. Kostishyn

A. V. Nuriev

V. Stefanik Karpaty National University:

B. K Ostafiychuk

G. V. Kurdyumov Institute of Physics of Metals, National Academy of Sciences, Ukraine:

V. V. Moklyak

In this work we studied polymer nanocomposites based on Fe₃O₄ nanoparticles and polyvinyl alcohol (PVA) using Müssbauer spectroscopy. The specimens were synthesized by chemical co−precipitation. The metal carriers were iron chlorides FeCl₃·6H₂O and FeCl₂·4H₂O, taken in a stoichiometric ratio of 2:1. The precursors were obtained by mixing metal salts with a PVA solution in deionized water. Seven specimens were obtained with polymer concentrations of 3, 5, 7 and 10% in the solution and Fe₃O₄ contents of 30, 45, 60 and 90%. Müssbauer spectra were recorded using a standard transmission method at 300 K and 90 K. The spectra were processed with the Univem Ms software using direct and gradient methods. The spectra of all the specimens are superpositions of the hyperfine magnetic structure and a doublet. The key goals were to determine the characteristics and structure of the composites as functions of synthesis conditions, understand the nature of the complex spectra and find which phenomena, i.e., superparamagnetism or non−stoichiometry, control the process. The best spectra decomposition providing for the minimum χ² were as follows: at 300 K the lines of the hyperfine structure spread out into 5 and 6 sextets and two doublets, and at 90 K, into 9 sextets and two doublets. This number of sextets due to the fact that the spectra represent not only the magnetic phase, but also low−magnetic ones with weaker magnetic fields at Fe⁵⁷ nuclei. The studies showed that the materials synthesized by us are discrete phases of a magnetic component the composition of which is close to the stoichiometric composition of magnetite with a small superparamagnetic contribution from a non−stoichiometric superparamagnetic component and an intermediate weakly magnetic superposition component. The paramagnetic component of the specimens pertains to the magnetite-maghemite series. The degree of non−stoichiometry of the weakly magnetic component cannot be evaluated, and one can only state this phase to be superparamagnetic.

1. Yu−Ving Mai. Polimernye nanokompozity / Yu−Ving Mai, Zhong−Zhen Yu. − M. : Tehnosfera, 2011. − 688 s.
2. Kayal, S. Doxorubicin loaded PVA coated iron oxide nanoparticles for targeted drug delivery / S. Kayal, R. V. Ramanujan // Mater. Sci. and Eng.: C. − 2010. − V. 30, Iss. 3. − P. 484—490.
3. Kozhitov, L. V. The effective method based on IR annealing for manufacturing novel carbon nanocrystalline material and multifunctional metal−polymer nanocomposites / L. V. Kozhitov, V. V. Kozlov, V. G. Kostishyn, A. T. Morchenko, D. G. Muratov // IOP Conf. Ser.: Mater. Sci. and Eng. − 2009. − N 5. − P. 012021.
4. Rubinstein, M. Investigation of the insulating phase of magnetite by NMR and Mossbauer effect / M. Rubinstein, D. W. Forester // Solid State Commun. − 1971. − V. 9. − P. 1675—1679.

5. Hargrove, R. S. Mossbauer measurements of magnetite below the Verwey transition / R. S. Hargrove, W. Kundig // Ibid. − 1970. − V. 8. − P. 303—308.
6. Kyundig, V. Issledovanie nekotoryh svoistv melkih chastic α−Fe₂O₃ c pomosh’yu effekta Messbauera / V. Kyundig, G. Bemmel’, D. Konstabaris, R. H. Dinndkvist − M. : Atomizdat, 1969. − S. 222—238.
7. Krupyanskii, Yu. F. Razmernye effekty v malyh chasticah Fe₃O₄ / Yu. F. Krupyanskii, I. P. Suzdalev // ZhETF. − 1974. − T. 67, vyp. 2(8). − S. 736—743.
8. Roggwiller, P. Mössbauer spectra of superparamagnetic Fe₃O₄ / P. Roggwiller, W. Kundig // Solid State Communication. − 1973. − V. 12. − P. 901—903.
9. Menil, F. Systematic trends of 57Fe Mössbauer isomer shifts in (FeOn) and (FeFn) polyhedra. Evidence of a new correlation between the isomer shift and the inductive effect of the competing bond T—X(−Fe) (where X is O or F and T element with a formal positive charge) / Menil F. // J. Phys. and Chem. of Solids. − 1985. − V. 46. − P. 763—789.
10. Huang, H. Mössbauer spectroscopy of protein−passivated iron oxide nanoparticles / H. Huang, R. Christmann, R. Ulber, V. Schu nemann // Hyperfine Interactions. − 2012. − V. 205, Iss. 1−3. − P. 121—124.
11. Oshtrakh, M. I. Magnetite nanoparticles as−prepared and dispersed in Copaiba oil: study using magnetic measurements and Mössbauer spectroscopy / M. I. Oshtrakh, M. V. Ushakov, A. S. Semenova, D. G. Kellerman, V. Sepelak, A. F. R. Rodriguez, V. A. Semionkin, P. C. Morais // Hyperfine Interactions. − 2013. − V. 219, Iss. 1−3. − P. 19—24.
12. Sawatzky, G. A. Recoilless−Fraction ratios for Fe⁵⁷ in octahedral and tetrahedral sites of a spinel and a garnet / G. A. Sawatzky, F. Van der Woude, A. H. Morrish // Phys. Rev. − 1969. − V. 183. − P. 383—386.
13. Volenic, K. A Mössbauer and X−ray diffraction study of nonstoichiometry in magnetite / K. Volenic, M. Seberini, J. Neid // Czechoslovak J. Phys. − 1975.− V. 25. − P. 1063—1071.