Oxides And Surface Magnetism Final Report

The general objective of this program was to study the magnetism and structure of iron oxide films with a view to enhancing control over growth mode, oxidation state and fundamental understanding in this complex system. In particular, the authors sought to create new magnetic metal/oxide multilayers and composites based on improved knowledge of the magnetic properties at Fe and Fe[sub 3]O[sub 4] surfaces and at Fe/Fe[sub 3]O[sub 4] interfaces. The project had three parts: (1) deposition and characterization of iron films up to 0.1[micro]m on fused quartz, (2) deposition and characterication of Fe[sub 3]O[sub 4] films up to 0.1[micro]m on fused quartz and (3) fabrication and characterization of Fe/Fe[sub 3]O[sub 4]/[hor-ellipsis]multilayers. (1) The structure and magnetic properties of sputtered Fe/SiO[sub 2] were studied first. The most interesting result here is the variation of magnetic properties with Fe film thickness, t. M[sub s] is approximately 1680 gauss and H[sub c][approx] 25 Oe for t> 0.1 micron. (2) The Fe oxide study (task 2) proved to be very important. By using reactive sputtering, the authors were able to locate a robust processing region, which would give thickness independent properties for the Fe[sub 3]O[sub 4] to be used in the multilayer studies. In addition they synthesized ferromagnetic Fe[sub 1[minus]x]O, the first report of such a phase. The ferromagnetism is attributed to the cation disorder. (3) The purpose of the multilayer study (task 3) was to see if Fe could be used to enhance the moment and possibly the coercivity of magnetic oxides.

The overall goal of this work was that presented in the original proposal: to pursue a program of spectroscopic research aimed at the understanding of low-dimensional transition metal oxides in high magnetic fields at the State University of New York at Binghamton.

The 5th International Workshop on Oxide Surfaces (IWOX-V) was held at Granlibakken Conference center in Lake Tahoe, CA, January 7-12. The total attendance was ~90. The breakdown of attendees by country is as follows: USA 41 Germany 18 Japan 7 UK 5 Italy 5 France 4 Austria 3 Denmark 3 Cech. Repub. 1 Ireland 1 New Zealand 1 India 1 The technical program included oral sessions on the electronic and magnetic properties of oxide surfaces, surface and interface structure, advances in theory, surface defects, thin film oxides on metals and on oxides, thin film metals on oxides, surface photochemistry, surface reactivity, and interactions with water. Two evening poster sessions had similar themes. As in previous years, the program stimulated significant interest and discussion among the attendees. The local expenses (food and lodging, $918 per person) for eight foreign invited speakers were covered by BES funds. In addition, partial reimbursement for travel ($328 per person) was supported by BES funds for two more foreign invited speakers.