| dc.contributor.author | Olson, Christopher Samuel | |
| dc.description.abstract | The chemical bond and its role as a mediator of magnetic exchange interaction remains an important aspect in the study of magnetic insulators and semiconductors. The M[TCNE] (M = transition metal, TCNE = tetracyanoethylene) class of organic-based magnets has attracted considerable interest since VII[TCNE]x (x ~ 2) exhibits one of the highest critical temperatures for its class – Tc ~ 400 K – in addition to highly spin-polarized conduction and valance bands (Eg ~ 0.5 eV), thus foreseeing potential spintronic application. The magneto-structural factors underlying this exceptional behavior remain elusive, however, due to the amorphous nature of the material. To address this, a novel synthetic route was utilized to produce new polycrystalline M[TCNE] solids (whose crystal structures have been resolved) with varying transition metal centers (Ni, Mn, Fe) and lattice dimensionality (2D-3D), exhibiting a wide range of Tc (40-170 K). Spectroscopic and magnetometric studies were performed and demonstrate that in 2D [MII(TCNE)(NCMe)2]X structures (M = Ni, Mn, Fe; X = diamagnetic anion), strong ligand-to-metal transfer of electron density from the organic TCNE radical plays a significant role in the formation of magnetic exchange pathways, while single-ion anisotropy strongly influences the critical temperature and below-Tc spin disorder for magnets in this material class. Additionally, using quantum-computational modeling, magnetic spin-density transfer trends, spin-polarized electronic structures, and electronic exchange coupling constants have been identified and interpreted in terms of 3d-orbital filling and dimensionality of magnetic interaction. These findings offer new perspectives on the stabilization of magnetic order in M[TCNE] solids. | en_US |
| dc.publisher | North Dakota State University | en_US |
| dc.rights | NDSU policy 190.6.2 | |
| dc.title | Synthesis, Characterization, and Modeling of New Molecule-Based Magnets | en_US |
| dc.type | Dissertation | en_US |
| dc.date.accessioned | 2018-03-19T19:24:45Z | |
| dc.date.available | 2018-03-19T19:24:45Z | |
| dc.date.issued | 2015 | en_US |
| dc.identifier.uri | https://hdl.handle.net/10365/27813 | |
| dc.rights.uri | https://www.ndsu.edu/fileadmin/policy/190.pdf | |
| ndsu.degree | Doctor of Philosophy (PhD) | en_US |
| ndsu.college | Graduate and Interdisciplinary Studies | en_US |
| ndsu.department | Materials and Nanotechnology | en_US |
| ndsu.program | Materials and Nanotechnology | en_US |
| ndsu.advisor | Pokhodnya, Konstantin | |
