STRUCTURE AND ANTIFERROMAGNETIC PHASE-TRANSFORMATION IN NANOCRYSTALLINE FEF2

被引：20

作者：

JIANG, J ^{[1
]}

RAMASAMY, S ^{[1
]}

BIRRINGER, R ^{[1
]}

GONSER, U ^{[1
]}

GLEITER, H ^{[1
]}

机构：

[1] UNIV MADRAS,DEPT NUCL PHYS,MADRAS 600025,TAMIL NADU,INDIA

来源：

SOLID STATE COMMUNICATIONS | 1991年 / 80卷 / 07期

关键词：

D O I：

10.1016/0038-1098(91)90065-4

中图分类号：

O469 [凝聚态物理学];

学科分类号：

070205 ;

摘要：

The effect of grain boundaries on the antiferromagnetic order/disorder transition of FeF2 has been investigated by means of Mossbauer spectroscopy. FeF2 specimens containing about 30% grain boundaries were generated in the form of polycrystals (called nanocrystalline FeF2) with an average crystal size of 8 nm. The nanocrystalline FeF2 was produced by means of inert gas condensation. The nanocrystalline FeF2 exhibited a broad range of transition temperature extending from 78 to 66 K as compared to the range of 78 to 75.5 K of coarse-grained FeF2. The magnetic relaxation of the nanocrystalline FeF2 sample was observed at 70 K. The Mossbauer spectrum of nanocrystalline FeF2 at 40 K consisted of two components: one component the Mossbauer parameters of which corresponded to coarse-grained FeF2 and a second component with an enhanced line width and a reduced hyperfine field of 295 kOe. The Debye temperature of the nanocrystalline FeF2 was found to be reduced to 86 K in comparison to 298 K of coarse-grained FeF2. All of these results indicate that the atomic structure in the grain boundaries is characterised by a reduction of the number of nearest neighbours and a dilatation of the interatomic spacings.

引用

页码：525 / 528

页数：4

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