Physical Sciences and Mathematics Commons^™

Exchange Coupling In Molecular Magnets: Zero, One And Three Dimensions, Asma Amjad

Electronic Theses and Dissertations

Molecular magnets with different dimensionality, whether they are zero-dimensional singlemolecule magnets (SMM) or one-dimensional single-chain magnets (SCM) are very interesting, since they allow probing the fundamental aspects bordering quantum and classical physics at the nanoscale level. This dissertation covers experimental studies of two Mn-based exchangecoupled molecule-based magnets and two Co-based single-chain magnets, using both dc Halleffect magnetometry and electron paramagnet resonance (EPR) techniques. In these multidimensional systems, the spin of the molecule exhibits quantum mechanical behavior at low temperature. It is quite interesting to observe the effect of magnetic exchange interactions on the magnetic properties of various complexes; hence they …

X-Band Rapid-Scan Epr, Deborah Gale Mitchell

Electronic Theses and Dissertations

The advantages of rapid-scan EPR relative to CW and pulse techniques for samples with long longitudinal relaxation time T₁ (N_s⁰ defects in diamond, N@C₆₀, and amorphous hydrogenated silicon), heterogeneous samples (crystalline 1:1 α,γ-bisdiphenylene-β-phenylallyl (BDPA):benzene), lossy samples (aqueous nitroxyl radicals), and transient radicals (5-tert-butoxycarbonyl-5-methyl-1-pyrroline-N-oxide (BMPO)-superoxide adduct) were studied.

For samples with long relaxation times, CW (continuous wave) EPR is challenging due to power saturation and distortions from passage effects. In rapid-scan EPR, the field is swept through resonance in a time that is short relative to T₂. In rapid-scan EPR, the magnetic field is …