The magnetic structure and the composition of Fe₃O₄/γ-Fe₂O₃ nanoparticles are studied at 300 and 80 K with Mössbauer spectroscopy. We found that the Fe₃O₄/γ-Fe₂O₃ particles are a core–shell nanocomposite (NC), in which magnetite Fe₃O₄ is covered with a maghemite shell (γ-Fe₂O₃). We showed that the thickness of the maghemite shell (γ-Fe₂O₃) depends on synthesis technology. We found that a layer, whose magnetic structure differs from that of the inner part of the shell (γ-Fe₂O₃), is formed on the surface of the maghemite shell (γ-Fe₂O₃) in the Fe₃O₄/γ-Fe₂O₃ NC. An intermediate layer is formed in the spin-glass state between the core and the shell. The data on structure of core–shell nanocomposites open up prospects to explain the properties of such particles, which are of great interest to use in various fields, including biomedicine.

中文翻译：

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组成和铁的磁路结构 ₃ ö ₄ /γ-的Fe ₂ ö ₃核-壳纳米复合材料在300和80 K：穆斯堡尔研究（第一部分）

磁结构和Fe的组合物₃ ö ₄ /γ-的Fe ₂ ö ₃进行了研究，在300纳米颗粒和80 K的穆斯堡尔谱。我们发现，铁₃ ö ₄ /γ-的Fe ₂ ö ₃颗粒是核-壳纳米复合材料（NC），其中磁铁矿的Fe ₃ ö ₄覆盖有磁赤铁矿壳（γ-的Fe ₂ ö ₃）。我们发现，磁赤铁矿壳（γ-Fe的厚度₂ ö ₃）取决于合成技术。我们发现了一层磁性结构不同于壳内部（γ-Fe₂ ø ₃），形成在磁赤铁矿壳的表面上的（γ-的Fe ₂ ö ₃）在铁₃ ö ₄ /γ-的Fe ₂ ö ₃ NC。在核和壳之间以旋转玻璃状态形成中间层。核-壳纳米复合材料的结构数据为解释此类颗粒的性质开辟了前景，这在包括生物医学在内的各个领域都非常有用。