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Synthesis and Properties of Cobalt Sulfide Phases: CoS 2 and Co 9 S 8
Author(s) -
Kumar Nitesh,
Raman Natarajan,
Sundaresan Athinarayanan
Publication year - 2014
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201300649
Subject(s) - cobalt , materials science , ferromagnetism , nanoparticle , magnetization , thermal decomposition , phase (matter) , electrical resistivity and conductivity , magnetoresistance , sulfide , analytical chemistry (journal) , relaxation (psychology) , hysteresis , cobalt sulfide , metal , condensed matter physics , chemistry , nanotechnology , metallurgy , magnetic field , psychology , physics , engineering , chromatography , quantum mechanics , electrochemistry , electrode , electrical engineering , social psychology , organic chemistry
Single phase cobalt disulfide (CoS 2 ) nanoparticles were prepared by thermal decomposition of cobalt‐thiourea complex at a low temperature (400 °C). CoS 2 nanoparticles exhibit ferromagnetic ordering at 122 K below which the temperature dependent resistivity of cold pressed nanoparticles deviates from metallic behavior and shows a broad maximum. Just below T C , it also exhibits a large magnetoresistance effect (6.5 %). A mixture of CoS and Co 9 S 8 phases were obtained between the temperature interval 400 °C < T < 1000 °C. At 1000 °C, a pure bulk Co 9 S 8 phase was obtained. It exhibits magnetic hysteresis typical of a ferromagnet at room temperature and a peak in magnetization at low temperature with a strong relaxation indicating possible spin glass state.