An approach is presented that allows quantifying the three dimensional magnetization pattern of a magnetic nanoobject from measured two dimensional Magnetic Force Microscopy (MFM) data. This is based on a MFM deconvolution approach, which quantitatively determines the effective surface charges, on a micromagnetic calculation of the total magnetic charges at and below the sample surface, and on a projection of the lower lying charges onto the sample surface for a comparison of the such obtained effective surface charges with the experimentally determined ones. Thus, by making use of the depth sensitivity of MFM and by applying a quantitative contrast analysis, we are able to reconstruct the inhomogeneous magnetization state at the end of individual cylindrical Fe52Co48 nanowires arranged in a triangular array. As a result, we prove the existence of a magnetic vortex state at their ends.

The behavior of bi- and trilayer coating systems for flexible a-Si:H based solar cells consisting of a barrier, an electrode, and an absorption layer is studied under mechanical load. First, the film morphology, stress, Young’s modulus, and crack onset strain (COS) were analyzed for single film coatings of various thickness on polyethylene terephthalate (PET) substrates. In order to demonstrate the role of the microstructure of a single film on the mechanical behavior of the whole multilayer coating, two sets of InSnOx (indium tin oxide, ITO) conductive coatings were prepared. Whereas a characteristic grain–subgrain structure was observed in ITO-1 films, grain growth was suppressed in ITO-2 films. ITO-1 bilayer coatings showed two-step failure under tensile load with cracks propagating along the ITO-1/a-Si:H-interface, whereas channeling cracks in comparable bi- and trilayers based on amorphous ITO-2 run through all constituent layers. A two-step failure is preferable from an application point of view, as it may lead to only a degradation of the performance instead of the ultimate failure of the device. Hence, the results demonstrate the importance of a fine-tuning of film microstructure not only for excellent electrical properties, but also for a high mechanical performance of flexible devices (e.g., a-Si:H based solar cells) during fabrication in a roll-to-roll process or under service.

The magnetization behavior of nanowires embedded in an array is influenced by the sum of the dipolar fields produced by all surrounding nanowires. These magnetostatic interactions largely modify the array properties and thus complicate the reconstruction of the ensemble averaged behavior of the individual nanowires, such as the intrinsic switching field distribution. Simply correcting the shearing of the hysteresis in a mean-field approach does not account for the locally fluctuating demagnetizing field, which originates from the individual magnetization configuration in the close surrounding of each nanowire. We present an in-field Magnetic Force Microscopy study of electrochemically produced Co48Fe52 nanowires, in which the influence of the magnetic nearest neighbor configuration on the switching behavior of the individual embedded nanowires is clearly detected. Based on this finding, a statistical evaluation method of nearest neighbor histograms is proposed, which potentially allows to judge the strength of the local magnetostatic interactions against the magnitude of the intrinsic switching field distribution.

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The magnetization behavior of nanowires arranged in an array is strongly influenced by the strength and shape of the demagnetizing field experienced by the individual nanowires. In order to understand the initial stage of the reversal process in nanowire arrays a hybrid method is proposed. First, an expression for the numerical calculation of the demagnetizing field in nanowire arrays is presented and compared to already available approaches. The derived expression calculates the demagnetizing field as a function of position along the length of an individual nanowire embedded in the array. In a second step, a micromagnetic simulation of the reversal process of a an isolated nanowire (1 μm) is superimposed with the earlier obtained field distribution. This enables including the inhomogeneity of the demagnetizing field of a large array (≈108 nanowires) into the micromagnetic simulation without the need of particularly large computing power. The simulation results show that in contrast to the switching in a single nanowire, where the reversal starts at the nanowire ends, the reversal under the influence of the array field strongly depends on the magnetization state of the whole array. Reversal can start either at the nanowire’s central region or at its ends.

The magnetic-domain resonance was studied for varying closure-domain structures in Co 40 Fe 40 B 20 thin-film elements. A domain-shape anisotropy model was introduced, by which a significant increase of the acousticdomain resonance frequency for decreasing domain width is predicted. We show that magnetic flux closure further increases the domain-width effect on the acoustic-domain resonance frequency. Furthermore, the domain resonance frequency is very sensitive to the effective width of the magnetic-domain walls due to dynamic dipolar interaction. The latter is quantified by calculating the dynamic wall width dependent dipolar fields. Domain-wall transitions in external magnetic fields manifest in either smooth or sudden resonance frequency changes, depending on the involved domain-wall types. Quantitative agreement between experimental and modeled data is obtained. Measuring the acoustic-domain resonance in small excitation fields therefore displays a method to analyze domain-wall instabilities and domain-wall interactions.