Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5491972 | Physica B: Condensed Matter | 2017 | 41 Pages |
Abstract
In this paper, we report on self-assembled Co nanoparticles deposited in and on porous silicon (PS) matrix by using UHV evaporation. Four samples were prepared by varying the Co deposited thickness (t = 3, 5, 7 and 10Â nm). All samples have been investigated by means of Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Physical Properties Measurement System (PPMS). The increase of t has induced an increase of the nanoparticle diameter from 3Â nm to about 150Â nm. Referring to the magnetic characterizations, this increase has been followed by a single to multi-domain transition. Therefore, this has been evidenced by a switching from superparamagnetism to purely ferromagnetism accompanied by a change in the magnetic reversal dynamics. Thus, by performing micromagnetic calculation, we have shown that a transition from the uniform rotation to vortex state occurs at a critical diameter of about 55Â nm.
Keywords
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Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
M. Saidani, W. Belkacem, L. Bessais, N. Mliki,