| Full text | |
| Author(s): |
Schio, P.
[1, 2]
;
Bonilla, F. J.
[2]
;
Zheng, Y.
[2, 3]
;
Demaille, D.
[2]
;
Milano, J.
[2, 3, 4, 5]
;
de Oliveira, A. J. A.
[1]
;
Vidal, F.
[2, 3]
Total Authors: 7
|
| Affiliation: | [1] Univ Fed Sao Carlos, Dept Fis, BR-13565905 Sao Paulo - Brazil
[2] UPMC, CNRS UMR 7588, Inst NanoSci Paris, F-75005 Paris - France
[3] LIFAN, Paris - France
[4] UNCU, CNEA CONICET, San Carlos De Bariloche, Rio Negro - Argentina
[5] UNCU, Inst Balseiro, San Carlos De Bariloche, Rio Negro - Argentina
Total Affiliations: 5
|
| Document type: | Journal article |
| Source: | JOURNAL OF PHYSICS-CONDENSED MATTER; v. 25, n. 5 FEB 6 2013. |
| Web of Science Citations: | 7 |
| Abstract | |
The magnetic relaxation of Co nanowires assemblies embedded in CeO2/SrTiO3(001) epilayers has been investigated by magnetization decay measurements. Two different samples were studied, with nanowires having distinct crystallographic structures and diameters of 3 and 5 nm. The structure of the nanowires was derived from high-resolution transmission electron microscopy analysis. The 3 nm diameter nanowires are made of hcp Co grains with the c-axis pointing along one of the four < 111 > directions of the CeO2 matrix, separated by fcc Co regions. In the 5 nm diameter nanowires, the grains are smaller and the density of stacking faults is much higher. The magnetic viscosity coefficient (S) of these two systems was measured as a function of the applied field and of the temperature. Analysis of the variation of S and of the activation volume for magnetization reversal reveals distinct behaviors for the two systems. In the nanowires assembly with 5 nm diameter, the results can be described by considering an energy barrier distribution related to shape anisotropy and are consistent with a thermally activated reversal of the magnetization. In contrast, the anomalous behavior of the 3 nm diameter wires indicates that additional sources of anisotropy have to be considered in order to describe the distribution of energy barriers and the reversal process. The distinct magnetic behaviors observed in these two systems can be rationalized by considering the grain structure of the nanowires and the resulting effective magnetocrystalline anisotropy. (AU) | |
| FAPESP's process: | 07/08649-5 - Magnetic and electronic properties in semiconducting oxides doped with transition metals |
| Grantee: | Pedro Schio de Noronha Muniz |
| Support Opportunities: | Scholarships in Brazil - Doctorate |
| FAPESP's process: | 08/10276-5 - Investigation of hybrid magnetic semicondutor nanostructures and multi-ferroic materials |
| Grantee: | Adilson Jesus Aparecido de Oliveira |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 11/03497-8 - Magnetization reversal in ultrathin Co ferromagnetic nanowires |
| Grantee: | Adilson Jesus Aparecido de Oliveira |
| Support Opportunities: | Research Grants - Visiting Researcher Grant - International |