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利用反滴共沉淀法制备了ＮｉＦｅ2O4纳米粒子，并在高压下（４.５ＧＰａ）压制成块状纳米固体材料．Ｘ射线衍射显示，ＮｉＦｅ2O4纳米固体的晶体结构和平均晶粒尺寸在高压下均没有发生变化．但其室温和低温穆斯堡尔谱结果表明，高压对纳米固体内部的磁相互作用和界面原子状态有很大的影响．在高压下，纳米固体内部的颗粒间磁偶极相互作用和界面离子间的超交换相互作用显著增强．从而明显抑制了ＮｉＦｅ2O4NiFe2O4 nanoparticles with on average grain size of 12nm were compacted into nanosolids under the pressure of 0.0—4.5GPa.The M?ssbauer spectra of NiFe2O4 nanosolids at room temperature and low temperatures show that high pressure has a strong influence on the magnetic interaction and interface atomic state inside the nanosolid,though the crystal structure and average grain size of nanosolid do not change under high pressure.Under high pressure,the superparamagnetic relaxation of NiFe2O4 nanosolid is suppressed obviously by the enhancement of the interparticle magnetic dipole interaction and the superexchange interaction among the interface ions in the nanosolid,and the magnetic anisotropy of it is also weakened by the interparticle magnetic coupling in it.At the same time,the symmetry and the degree of short-range order of the polyhedrons are raised gradually with the increase of pressure,and then the atomic structure in the surface and interface zone of NiFe2O4 nanosolid shows a tendency to change into the grain boundary structure of common polycrystalline solid with large grain size.
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物理学报. 1997, 46(12): 2442-2453.
doi: 10.7498/aps.46.2442.
NiFe2O4纳米固体的穆斯堡尔谱研究
- 收稿日期: 1997-05-04
- 刊出日期: 1997-06-05
摘要: 利用反滴共沉淀法制备了ＮｉＦｅ2O4纳米粒子，并在高压下（４.５ＧＰａ）压制成块状纳米固体材料．Ｘ射线衍射显示，ＮｉＦｅ2O4纳米固体的晶体结构和平均晶粒尺寸在高压下均没有发生变化．但其室温和低温穆斯堡尔谱结果表明，高压对纳米固体内部的磁相互作用和界面原子状态有很大的影响．在高压下，纳米固体内部的颗粒间磁偶极相互作用和界面离子间的超交换相互作用显著增强．从而明显抑制了ＮｉＦｅ2O4
English Abstract
M?SSBAUER SPECTROSCOPY STUDY OF NiFe2O4 NANOSOLID COMPACTED UNDER HIGH PRESSURE
- Received Date:
04 May 1997
- Published Online:
05 June 1997
Abstract: NiFe2O4 nanoparticles with on average grain size of 12nm were compacted into nanosolids under the pressure of 0.0—4.5GPa.The M?ssbauer spectra of NiFe2O4 nanosolids at room temperature and low temperatures show that high pressure has a strong influence on the magnetic interaction and interface atomic state inside the nanosolid,though the crystal structure and average grain size of nanosolid do not change under high pressure.Under high pressure,the superparamagnetic relaxation of NiFe2O4 nanosolid is suppressed obviously by the enhancement of the interparticle magnetic dipole interaction and the superexchange interaction among the interface ions in the nanosolid,and the magnetic anisotropy of it is also weakened by the interparticle magnetic coupling in it.At the same time,the symmetry and the degree of short-range order of the polyhedrons are raised gradually with the increase of pressure,and then the atomic structure in the surface and interface zone of NiFe2O4 nanosolid shows a tendency to change into the grain boundary structure of common polycrystalline solid with large grain size.
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