Surface magnetic structure of epitaxial magnetite thin films grown on MgO (001) A long-range ordered magnetic domain structure was found in magnetitelike ͑Fe 3−␦ O 4 , ␦ Ϸ 0.03͒ thin films prepared by molecular beam epitaxy on MgO ͑100͒ substrates. The stripelike magnetic domain structure arising after suitable postprocessing differs significantly from earlier observations. The field-dependent domain structure was investigated by magnetic force microscopy in external magnetic fields. The magnetic domain structure results from a moderate perpendicular anisotropy. The domain structure is pinned, and the pinning centers arise from the magnetite antiphase domain structure.

We study numerically the influence of momentum-conserving dephasing on the transport in a disordered chain of scatterers. Loss of phase memory is caused by coupling the transport channels to dephasing reservoirs. In contrast to previously used models, the dephasing reservoirs are linked to the transport channels between the scatterers, and momentum conserving dephasing can be investigated. Our setup provides a model for nanosystems exhibiting conductance quantization at higher temperatures in spite of the presence of phononic interaction. We are able to confirm numerically some theoretical predictions.

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This work presents an investigation of the magnetization processes in out-of-plane textured SmCo5 thin films by means of domain observations with magnetic force microscopy (MFM). Starting from the thermally demagnetized state, an applied field was increased stepwise until saturation, and the magnetic domain pattern was recorded at the respective field. Additionally, the change in the domain structure was investigated for the demagnetization branch to observe the full reversal process from positive to negative saturation. In a second experiment, various opposite fields were applied to the film after previous saturation and the time-dependent domain evolution was measured. The directly observed domain behaviour specifies the influence of pinning and nucleation on the magnetizing and demagnetizing process. From these time-dependent domain images, magnetization curves were constructed and the resulting viscosity is compared with data from global magnetization measurements. The viscosity as determined from MFM data is measurably larger than that deduced from global relaxation measurements, which demonstrates the influence of the tip's magnetization on the reversal mechanism.