376 research outputs found
Temperature dependence of the coercive field in single-domain particle systems
The magnetic properties of Cu97Co3 and Cu90Co10 granular alloys were measured
over a wide temperature range (2 to 300K). The measurements show an unusual
temperature dependence of the coercive field. A generalized model is proposed
and explains well the experimental behavior over a wide temperature range. The
coexistence of blocked and unblocked particles for a given temperature rises
difficulties that are solved here by introducing a temperature dependent
blocking temperature. An empirical factor gamma arise from the model and is
directly related to the particle interactions. The proposed generalized model
describes well the experimental results and can be applied to other
single-domain particle system.Comment: 7 pages, 8 figures, revised version, accepted to Physical Review B on
29/04/200
Ultrahigh field MRI in clinical neuroimmunology: a potential contribution to improved diagnostics and personalised disease management
Conventional magnetic resonance imaging (MRI) at 1.5 Tesla (T) is limited by modest spatial resolution and signal-to-noise ratio (SNR), impeding the identification and classification of inflammatory central nervous system changes in current clinical practice. Gaining from enhanced susceptibility effects and improved SNR, ultrahigh field MRI at 7Â T depicts inflammatory brain lesions in great detail. This review summarises recent reports on 7Â T MRI in neuroinflammatory diseases and addresses the question as to whether ultrahigh field MRI may eventually improve clinical decision-making and personalised disease management
Determination of closure domain penetration in electrodeposited microtubes by combined magnetic force microscopy and giant magneto-impedance techniques
The domain structure of electrodeposited Co90P10 microtubes exhibiting radial magnetic anisotropy and giant magneto-impedance effect has been characterized by combined magnetic force microscopy imaging and impedance measurements. It has been shown that the size of the closure domains increases with the CoP layer thickness. Furthermore, the depth of the closure domains has been quantitatively determined from the high frequency behavior.The authors want to thank Professor J. Miltat for helpful discussions. This work has been performed under Project No. CAM/07N/0033/1998. A. Asenjo would like to thank the CAM (Spain) for the postdoctoral fellowship. J. P. Sinnecker thanks the Brazilian agencies CNPq and FAPERJ for the
financial support.Peer reviewe
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