Date of Award
2015-01-01
Degree Name
Master of Science
Department
Physics
Advisor(s)
Cristian E. Botez
Abstract
In this investigation we use two complementary techniques to distinguish between superparamagnetic blocking (SPB) and superspin-glass (SSG) freezing phenomena in magnetite nanoparticles. While these manifestations of the superspin dynamics are fundamentally different, they have similar "signatures", especially in dc-magnetization experiments. Even if ac-susceptibility measurements are employed, careful use of mathematical models to analyze the data are needed to uncover which type of phenomena (SPB or SSG freezing) occurs within the material. Yet, by utilizing electron paramagnetic resonance (EPR) on a 10 nm Fe3O4 nano-powder as well as on a ferrofluid (based on the same nanoparticle ensemble) we found a very distinct difference in the absorption spectra between the two samples, which indicates markedly different EPR signatures from SPB and SSG freezing behaviors.
Language
en
Provenance
Received from ProQuest
Copyright Date
2015
File Size
42 pages
File Format
application/pdf
Rights Holder
Alex D. Price
Recommended Citation
Price, Alex D., "AC-Susceptibility and EPR Investigations of Superspin Dynamics in Magnetite Nanoparticles" (2015). Open Access Theses & Dissertations. 1127.
https://scholarworks.utep.edu/open_etd/1127