Fe$\sb3$O$\sb4$ (magnetite) is a ferromagnetic semiconductor while NiO is an antiferromagnetic insulator with a room temperature resistivity at least six orders of magnitude greater than that of Fe$\sb3$O$\sb4.$ Modulated structure films, with equal Fe$\sb3$O$\sb4$ and NiO layer thicknesses, were grown using plasma assisted molecular beam epitaxy to a total film thickness of 3446A, and with modulation wavelengths $\Lambda$ (bilayer thicknesses) ranging from 16A to 1763A. Post growth $\theta$-2$\theta$ x-ray data contain well defined low angle peaks which confirm that the targeted layer thicknesses were accurately achieved. Resistivity has been measured perpendicular to the plane of the film, as a function of modulation wavelength and temperature. A dependence of the resistivity on $\Lambda$ is observed in two sample sets in which the resistivity rapidly increases many orders of magnitude as the modulation wavelength decreases from the bulk $\Lambda\rightarrow\infty$ limit in the vicinity of 600A. This length scale dependent resistivity enhancement of the Fe$\sb3$O$\sb4$/NiO modulated structures cannot be explained by the standard model of interfacial resistance. A qualitative argument is presented for a metal-insulator-metal interfacial charge transfer model which contains both the resistivity enhancement and the observed length scale dependence. / Source: Dissertation Abstracts International, Volume: 57-04, Section: B, page: 2634. / Major Professor: L. R. Testardi. / Thesis (Ph.D.)--The Florida State University, 1996.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_77722 |
| Contributors | Smathers, Jay Brady., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 121 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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