Effect of Defects on the Magnetic Properties of 2D Films Using Patterned Substrates

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9623283 Conrad This project will investigate how structural defects on length scales approaching 2 nm will affect the magnetic properties. The project has technological importance because the demand for higher storage densities in recording media is expected to push magnetic clusters sizes below a 2 nm radius. A novel set of patterned tungsten substrates will be used to carry out such a study. These surfaces consist of a periodic staircase with each step one atom high. By controlled growth conditions, 2-dimensional iron films can be forced to grow out from the substrate steps to produce equal spaced one-dimensional magnetic wires. The gaps between these wires play the role of imperfections in a 2-dimensional magnetic film. Since both wire width (2 to 10 atoms and wire separation (1 to 20 atoms) can be independently varied, we will explore finite wire width effects and coupling between isolated wires on the iron film's magnetic properties. The work will be carried out using a combination of high resolution Low Energy Electron Diffraction, Surface Magneto-Optical Kerr effect, and Scanning Tunneling Microscopy. %%% The influence of atomic defects on magnetic film properties will play an important role in developing the next generation of high density recording media. The demand for higher storage densities is expected to push the diameter of magnetic clusters down to sizes of 6 to 10 atoms. It is therefore important to understand how magnetic properties are affected by limiting the magnetic films to contain less than 100 atoms. We have devised a novel technique to grow arrays of thin (3 to 10 atoms wide) parallel magnetic wires. These wires will be used to study how wire thickness and wire separation influence their magnetic properties. The critical wire thickness required to develop a magnetic moment and the effects of neighboring wires on th e magnetic properties of an individual wire will be studied. ***