Domain structure of iron single crystals grown on Si(111) investigated by magnetic force microscopy (abstract)

Abstract

Single-crystal iron films grown epitaxially on (111) silicon were studied using a magnetic force microscope (MFM). The crystalline anisotropy easy axes (〈100〉), directed 35° out of the film plane, result in a significant magnetic charge density at the film surface and a sixfold symmetry in the energy minima of the system. To reduce the magnetostatic energy of this configuration, an alternating, stripe domain pattern formed in samples of thickness ranging from 1240 to 315 nm. Because of the wavelike form of the MFM response across the stripes, two-dimensional Fourier transforms of the MFM images were used to give measures at the domain period, i.e., the wavelength of the stripes, as well as the complexity of the patterns. The stripe domain period was found to be approximately equal to the film thickness which is consistent with previous theoretical predictions. The domain patterns of the films in various remanent states and progressive stages of the magnetization process were investigated using the MFM and an in situ, variable magnetic field. A MFM tip that is magnetically soft compared to the iron is most suitable for this. Measurements of the domain period and pattern complexity as a funciton of applied field were correlated with bulk hysteresis measurements.