Magnetic properties of nanocrystalline Cr2O3 synthesized in a microwave plasma

被引：86

作者：

Vollath, D ^{[1
]}

Szabo, DV ^{[1
]}

Willis, JO ^{[1
]}

机构：

[1] LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545

来源：

MATERIALS LETTERS | 1996年 / 29卷 / 4-6期

关键词：

chromium sesqui oxide; nanocrystalline; magnetic properties; superparamagnetism; microwave plasma synthesis;

D O I：

10.1016/S0167-577X(96)00158-9

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Nanocrystalline Cr2O3 particles were synthesized in a microwave plasma using chromium hexacarbonyl as precursor. Electron microscopy revealed that the particle diameter is, depending on the process parameters, in the range from 7 to 9 nm or from 5 to 6 nm. In the case of the larger particles, additionally elongated ones with a diameter from 6 to 7 nm and a length from 10 to 15 nm, were found, The larger particles were found to be single crystals. The smaller particle fraction showed a granular substructure, resembling to a polycrystalline particle. The size of these granules is in the range from 2 to 3 nm. The structure of the material was determined by electron diffraction to be the rhombohedral corundum structure. In the temperature range from 10 to 300 K the magnetic behavior can be described by a modified Langevin function but with a magnetic moment having a thermally activated component. In any event, in this temperature range the assumption K upsilon much less than kT is valid, where K is the anisotropy energy and upsilon, the particle volume. The thermally activated magnetization can be attributed to the material with the granular substructure. The size of the magnetic domains was found to be identical with the electronmicroscopically determined size of the granules.

引用

页码：271 / 279

页数：9

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