Abstract
The influence of preparation conditions on the structure of poly(vinyl alcohol)-Fe3O4 nanocomposites was examined. The size of single-crystal single-domain particles of the magnetic nanophase (similar to 3-80 nm) Z' and their degree of aggregation during the synthesis of magnetite at high pH values were found to be determined to a considerable extent by the microviscosity of the reaction medium. A dramatic increase in coercivity (9 x 10(-4)-90 x 10(-4) T) with an increase in the degree of aggregation is due to the presence of strong interactions between magnetic particles in compact aggregates.