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Magnetic properties of Zn 0.7 Co 2.3 O 4+ δ spinel prepared by thermal decomposition of binary oxalates in air
Author(s) -
Bazuev G. V.,
Gyrdasova O. I.
Publication year - 2008
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200743486
Subject(s) - oxalate , spinel , cobalt , paramagnetism , magnetic susceptibility , thermal decomposition , magnetization , atmospheric temperature range , ferromagnetism , materials science , analytical chemistry (journal) , oxide , decomposition , chemistry , crystallography , inorganic chemistry , condensed matter physics , magnetic field , thermodynamics , metallurgy , physics , organic chemistry , chromatography , quantum mechanics
Magnetization and ac susceptibility of two Zn 0.7 Co 2.3 O 4+ δ spinel specimens obtained by decomposition of the binary oxalate Zn x Co 1– x C 2 O 4 ·2H 2 O in air were measured in the temperature range 2–300 K. It is shown that the complex oxide Zn 0.7 Co 2.3 O 4+ δ formed right after the decomposition of the oxalate (at 220 °C) contains about 0.002 mass% metal cobalt, which is responsible for the dependence of the magnetic susceptibility χ on magnetic field at 300 K. Below 100 K, the χ = f ( T ) dependence of this specimen is characterized by divergence between curves measured under ZFC and FC conditions and a magnetic hysteresis loop at 2 K. The specimen synthesized at 700 °C does not contain a ferromagnetic component and is paramagnetic in the temperature interval 2–300 K. The observed differences in magnetic properties are explained by a higher degree of oxidation of cobalt and the nanodimensional state of the compound formed at a lower temperature. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)