Chemical and Materials Engineering Vol. 2(3), pp. 58 - 71
DOI: 10.13189/cme.2014.020302
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Structural Properties of Mechanically Activated Rare-Earth Manganites


O.M. Fedorova 1, A.V. Fetisov 1, A.Ya. Fishman 1, G.A.Kozhina 1,*, Kurennykh T.E. 2, Vedmid` L.B. 1, Vykhodets V.B. 2
1 Institute of Metallurgy, Ural Branch of Russian Academy of Sciences, Ekaterinburg, 620016, Russia
2 Institute of Metal Physics, Ural Branch of Russian Academy of Sciences, Ekaterinburg, 620990, Russia

ABSTRACT

The effect of mechanical processing in different types of activators on the structure and physicochemical properties of the oxides LnMnO3+δ (Ln = Sm, Nd, La) has been studied. The optimal modes of mechanical activation for transformation the oxides under consideration to nanostructured state have been defined. Mechanical processing has been shown to cause a significant change of Jahn-Teller distortion parameters and temperatures of the cooperative Jahn-Teller phase transition. The presence of connection between redox processes and destruction of orbital ordering has been demonstrated. Very low values (10-21-10-24 m2/s) of the oxygen bulk diffusion coefficient have been obtained for the oxides under consideration in the temperature range of 400 - 750℃. The diffusion activation energies are close to 1 eV, indicating the oxygen diffusion proceeds through structural defects at these temperatures.

KEYWORDS
Rare-Earth Manganites, Mechanical Activation, X-ray Diffraction, Jahn-Teller transition, Oxygen Diffusion

Cite this paper
O.M. Fedorova , A.V. Fetisov , A.Ya. Fishman , G.A.Kozhina , Kurennykh T.E. , Vedmid` L.B. , Vykhodets V.B. (2014). Structural Properties of Mechanically Activated Rare-Earth Manganites. Chemical and Materials Engineering, 2 , 58 - 71. doi: 10.13189/cme.2014.020302.