Nanostructure, composition and magnetic properties in soft and hard Co-Ni nanoparticles:: The effect on the magnetic anisotropy

被引：11

作者：

Fernandez, C. de Julian ^{[1
,2
,3
]}

Sangregorio, C. ^{[1
,2
]}

Innocenti, C. ^{[1
,2
]}

Mattei, G. ^{[3
]}

Mazzoldi, P. ^{[3
]}

机构：

[1] Univ Florence, Dept Chem, I-50019 Florence, Italy

[2] Univ Florence, INSTM Res Unit, I-50019 Florence, Italy

[3] Univ Padua, Dept Phys, I-35131 Padua, Italy

来源：

INORGANICA CHIMICA ACTA | 2008年 / 361卷 / 14-15期

关键词：

Co-Ni nanoparticles; superparamagnetism; magnetic anisotropy; surface anisotropy; interparticle interactions;

D O I：

10.1016/j.ica.2008.03.116

中图分类号：

O61 [无机化学];

学科分类号：

070301 ; 081704 ;

摘要：

The magnetic properties of Co-Ni alloys nanoparticles with composition Co80Ni20 and Co50Ni50 and dispersed in a silica matrix are investigated. The effective magnetic anisotropies are evaluated from the analysis of the temperature dependence of the zero-field-cooling magnetizations and from the hysteresis loops at 3 K considering the coherent rotation model. The results show that, on the contrary of what expected, Co80Ni20 nanoparticles have smaller anisotropy than the Co50Ni50 one showing that the magnetic properties of the system can be tuned from soft to hard by simply adjusting the alloy composition. This behaviour can be explained on the basis of the different size and composition of the two systems. Moreover we found that the evaluation of the anisotropy constant depends on the experimental method adopted due to the modifications by interparticle dipolar interactions of the reversal process. (C) 2008 Elsevier B.V. All rights reserved.

引用

页码：4138 / 4142

页数：5

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