Mechanochemical Preparation and Magnetic Properties of Fe3O4/ZnS Nanocomposite
Z. Bujňákováa, A. Zorkovská a, J. Kováč b
aInstitute of Geotechnics, SAS, Watsonova 45, 040 01 Košice, Slovakia
bInstitute of Experimental Physics, SAS, Watsonova 47, 040 01 Košice, Slovakia
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Powder nanocomposite of Fe3O4/ZnS was prepared by mechanochemical synthesis in a planetary ball mill. In this reaction natural magnetite mineral Fe3O4 was used, together with zinc acetate (CH3COO)2Zn·2H2O and sodium sulfide Na2S·9H2O, as precursors for the zinc sulfide ZnS. X-ray diffraction revealed that the sample is composed of small nanocrystalline particles, containing Fe3O4 and ZnS. The non-milled magnetite showed distinctive Verwey transition at around 120 K, this becomes suppressed after milling, as a consequence of structural disorder and presence of defects. Moreover, the reduction of saturation magnetization from 91 A m2/kg to 69.2 A m2/kg was observed, as a consequence of the milling process. The magnetization of the Fe3O4/ZnS nanocomposite was the lowest (34.5 A m2/kg), due to the milling and to the decreased weight fraction of the ferrimagnetic component. Nevertheless, the Fe3O4/ZnS sample demonstrates ferrimagnetic behavior as well, and its structure is less perturbed by milling, the Verwey transition, although less impressive, but is preserved.

DOI: 10.12693/APhysPolA.131.1120
PACS numbers: 81.07.Bc, 81.20.Ev, 81.20.Wk