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首页> 外文期刊>Physica, B. Condensed Matter >Saturation magnetization of gamma-Fe2O3 nanoparticles dispersed in a silica matrix
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Saturation magnetization of gamma-Fe2O3 nanoparticles dispersed in a silica matrix

机译:分散在二氧化硅基质中的γ-Fe2O3纳米粒子的饱和磁化强度

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The relative variation of the saturation magnetization of non-interacting nanoparticles of gamma-Fe2O3 (0.68 vol%) that are isolated in an amorphous SiO2 matrix is of 69.7% when the temperature decreases from 300 to 77 K. This variation is much higher than the relative variation of the spontaneous magnetization corresponding to bulk ferrite, which is of only 9.5% in the same temperature range. We have attributed the observed anomaly to the increase of the mean magnetic diameter of the particles (attached to the particle's core where the spins are aligned due to the superexchange interaction) from 10.20 to 11.76 nm when the temperature decreases from 300 K to the temperature of liquid nitrogen. The increase of the magnetic diameter is caused by the presence of a paramagnetic layer on the particle surface, a layer that becomes ferrimagnetically ordered at low temperatures. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 43]
机译:当温度从300降低到77 K时,在无定形SiO2基质中分离的非相互作用的γ-Fe2O3纳米粒子(0.68%(体积))的饱和磁化强度的相对变化为69.7%。自发磁化的相对变化对应于块状铁素体,在相同温度范围内仅为9.5%。我们将观察到的异常归因于当温度从300 K降低到200°C时,颗粒的平均磁直径(由于超交换相互作用而附着在自旋对准的颗粒核上)从10.20 nm增加到11.76 nm。液氮。磁直径的增加是由于粒子表面上存在顺磁性层引起的,顺磁性层在低温下会变成亚铁磁性有序。 (C)2002 Elsevier Science B.V.保留所有权利。 [参考:43]

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