This thesis is devoted to the studies of structural and magnetic properties of Pd/Fe multilayers with the principal goal of determining the extent to which the Pd layers are polarised by the Fe atoms and the average moment induced on each Pd atom. Although Pd/Fe multilayers have been the subject of several previous studies, no consensus on the behavior of magnetically polarised Pd has emerged. This work has the novel feature of applying a wide range of characterization techniques on the same sample. These techniques included x-ray diffraction, conversion electron Mossbauer spectroscopy (CEMS), magnetometry and polarised neutron reflectometry. Ag/Fe multilayers were first characterized to confirm the validity of the analysis of the small-angle x-ray reflectivity to obtain layer thicknesses, as well as to determine the temperature dependence of the Fe moment from GEMS data. / From the intersection of the results from the complementary measurements on Pd/Fe multilayers, for the first time, an unequivocal understanding of the behavior of magnetically polarised Pd has been achieved. We find, there is a clear excess magnetisation associated with Pd polarisation. At 4.5 K, the Pd in contact with an Fe surface is polarised with an average moment of 0.32 +/- 0.02 muB to a depth of 20 +/- 4 A (9 +/- 2 atomic layers). These results indicate a large exchange splitting of the Pd d-bands for a significant distance from the Fe surface, leaving the spin-up band full, and a moment in the Pd arising from the 0.36 holes in the spin-down band. We also find that the Fe moment at the Pd/Fe interface is slightly enhanced to 2.42 +/- 0.05 muB for about 2.0 +/- 0.3 atomic layers, suggesting that the magnetic properties of Fe is less affected by Pd as compared to the influence of Fe on Pd. Neither the extent of Pd polarisation nor the interface Fe moment agree with values predicted by theoretical calculations (the calculated Pd polarisation depth is 2 atomic layers, and the interface Fe moment is 2.7 muB). The band structure calculations will have to be refined in the light of the results from current study.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.85061 |
| Date | January 2004 |
| Creators | Cheng, Li, 1973- |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Physics.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 002180126, proquestno: AAINR06285, Theses scanned by UMI/ProQuest. |
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