Results from magnetic viscosity experiments on chemically synthesized magnetic nanoparticles are presented. Our synthesized Fe20Pt80 particles are distinguished by a narrow size distribution but display features associated with broad distributions of activation rates. Results are presented from viscosity measurements in which the remnant magnetization is measured at different times after the removal of a static field, and studied as a function of temperature. We discuss how these results may be analyzed in terms of activation rate distributions for thermal activated reversal processes after the application and removal of a field. A method for the extraction of energy barrier distributions from directly measured time dependent data is presented.
History
Publication title
Journal of Applied Physics
Volume
97
Issue
10
Article number
10J508
Number
10J508
Pagination
1-3
ISSN
0021-8979
Department/School
School of Natural Sciences
Publisher
A I P Publishing LLC
Place of publication
United States
Rights statement
Copyright 2005 American Institute of Physics
Repository Status
Restricted
Socio-economic Objectives
Expanding knowledge in the chemical sciences; Expanding knowledge in the physical sciences