Мёссбауэровские исследования состава и магнитной структуры нанокомпозитов Fe-=SUB=-3-=/SUB=-O-=SUB=-4-=/SUB=-/γFe-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=- типа ядро--оболочка при температура 300 и 80 K (Часть I)

The results of Mössbauer studies of the magnetic structure and composition of Fe3O4 / γ-Fe2O3 nanoparticles at temperatures of 300 and 80 K are presented. It was found that particles Fe3O4 /γ-Fe2O3 is a core / shell nanocomposite (NC) in which magnetite (Fe3O4) is a coated by shell of maghemite (γ-Fe2O3). It was shown that the thickness of the maghemite (γ-Fe2O3) shell depends on the synthesis technology. It was found that, in the Fe3O4 /γ-Fe2O3 NC, on the surface of the maghemite (γ-Fe2O3) shell, a layer whose magnetic structure differs from the structure of the inner part of the shell (γ-Fe2O3). An intermediate layer is formed between the core and the shell in a spin-glass state. The obtained data on the structure of core / shell nanocomposites open up prospects for explaining the properties of such particles, which are of great interest for applications in various fields, including biomedicine.