John Boeckl (Committee Member), Gregory Kozlowski (Advisor), Doug Petkie (Committee Member)
Master of Science (MS)
This Thesis studies the relationship between diameter (size) of ferromagnetic nanoparticles and Curie temperature. Iron nanoparticles with different diameters from 5.9 nm to 21.4 nm were prepared by thermal decomposition of iron pentacarbonyl in the presence of oleic acid/octyl ether at Cambridge University, United Kingdom. Heating response of these ferromagnetic nanoparticles suspended in water were measured experimentally during which the same amount of iron nanoparticles and di-ionized water were subjected to an alternating magnetic field and the increase in temperature of these samples was measured. Heating performance of nanoparticles was described by Specific Absorption Rate (SAR). Heating and cooling rate were also calculated as a function of time and relationship of the rates to the temperature of magnetic nanoparticle was established. Based on linear fits of these rates, an extrapolation to the higher temperature of heating and cooling rate resulted in an intersection of the lines. The point of intersection was interpreted based on the theoretical consideration as a critical or Curie temperature. The critical temperature measurements of ferromagnetic nanoparticles of iron using our calorimetry seemed to be straightforward, reliable, and relatively cheap in comparison to well established techniques such as magnetization, susceptibility, or heat capacity measurements.
Department or Program
Department of Physics
Year Degree Awarded
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