Study of Magnetization and Critical Temperature for Nanomagnetic Particles
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Date
2011-06
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Addis Ababa University
Abstract
Magnetic nanostructures, such as dots and dot arrays, nanowires, multilayers and nano-
junctions, are reviewed and compared with bulk magnets. By using the Gibbs free energy
variational principle based on the Bogoliubov inequality the magnetic properties and crit-
ical behavior of metallic nanoparticles having concurrently atomic disorder, dilution and
competing interactions, are studied within the framework of an Ising model. As a case
of study we have considered the Fe0:5Mn0:1Al0:4 alloy characterized for exhibiting, un-
der bulk conditions, low temperature reentrant spin glass (RSG) behavior and for which
experimental and simulation results are available. Our results allow concluding that the
variational model is successful in reproducing features of the dependence of the critical
temperature with particle size and low temperature magnetization reduction consistent
with a RSG behavior. In this work we compute the magnetization per site and the mag-
netic susceptibility, as a function of temperature, for di erent values of the coordination
number
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Keywords
Magnetic Nanostructures