Cobalt perovskite oxides and their derivatives are intensively studied because of their complex

electronic and magnetic properties, that are very attractive for many technological applications.

Physical properties of such systems depend strongly on the oxygen deficiency and can be modified by

choosing appropriate preparation conditions [1]. The development of novel production methods are

thus of particular interest. Herein, we present the synthesis of strontium cobaltite nanopowder from

coordination molecular precursor Co-Sr-2,3-PDC (1) [2] by a thermal decomposition method as well

as structural, magnetic and transport characterization of the composite obtained. Compound 1 exhibits

a 2D coordination polymer structure, where the ligands link Co(II) and Sr(II) ions in the molar ratio

1:1; the shortest cobalt-cobalt distance is 6.42 Å. The TGA thermal analysis proves that complex 1

undergoes a controlled thermal decomposition to give a Co-Sr mixed metal oxide residue 2, which

after cooling in air was determined by PXRD as Sr6Co5O15xCo3O4 (CPDC Nr 01-086-0614, and Nr 00-

042-1467). The chemical composition and surface morphology analyzed by SEM microscopy and ED

X-ray, suggest the formation of crystallite mixture of Sr6Co5O15xCo3O4 with well-defined crystalline

particles evently distributed in the range 1-3 μm. Variable temperature magnetic measurements of 1

and 2 have been performed in the range 5 – 330 K. The magnetic studies of polycrystalline sample 1

show the dominant paramagnetic behavior of high-spin (S = 3/2) Co(II) ions (fig.1). While for sample

2, magnetometry results demonstrate the presence of a major compound Sr6Co5O15 (fig.2) with a small

inclusions of SrCoO2.75, probably, remaining as an insignificant part of the intermediate phase. The

electrical conductivity (σ) of 2 have been investigated in the temperature range 75 – 330 K. It shows

semiconducting-like behavior with values of σ in the range ~10-6 – 10-1 Ω-1cm-1, that is in good

agreement with the expectation for 2H-hexagonal Sr6Co5O15 [3]. In the high temperature range (200 –

330 K) an activation energy of the material (Ea) was estimated at Ea ~ 0.23 eV.

[1] L.G.Hubert-Pfalzgraf, Inorg. Chem.Commun., 2003, 6, 102.

[2] A. Lazarescu, E. Melnic, V. Kravtsov, C. Turta, Proceedings of the Intern. Conf.on Oxide Materials for

Electronic Engineering –fabrication, properties and applications (OMEE-2012), sept., 3-7, 2012, Lviv, Ukraine,

p. 299-300.