Using soft-x-ray resonant magnetic scattering in combination with first-principles calculations for noncollinear magnetic configurations we present a new model of the magnetism in ultrathin fcc Fe films on Cu(001). We find the presence of blocks with robust magnetic structure, while the relative directions of the moments of different blocks are sensitive to the detailed atomic structure and temperature. The magnetic noncollinearity is directly demonstrated, which has not been possible so far.

More than three decades ago, at Fraunhofer IZFP, research activities that were related to the application of micromagnetic methods for nondestructive testing (NDT) of the microstructure and the properties of ferrous materials commenced. Soon, it was observed that it is beneficial to combine the measuring information from several micromagnetic methods and measuring parameters. This was the birth of 3MA-the micromagnetic multi-parametric microstructure and stress analysis. Since then, 3MA has undergone a remarkable development. It has proven to be one of the most valuable testing techniques for the nondestructive characterization of metallic materials. Nowadays, 3MA is well accepted in industrial production and material research. Over the years, several equipment variants and a wide range of probe heads have been developed, ranging from magnetic microscopes with µm resolution up to large inspection systems for in-line strip steel inspection. 3MA is extremely versatile, as proved by a huge amount of reported applications, such as the quantitative determination of hardness, hardening depth, residual stress, and other material parameters. Today, specialized 3MA systems are available for manual or automated testing of various materials, semi-finished goods, and final products that are made of steel, cast iron, or other ferromagnetic materials. This paper will provide an overview of the historical development, the basic principles, and the main applications of 3MA.

Shafts for power generation machines have to be inspected in regards to the mechanical-technological properties of the final product material. In order to save time and costs, the non-destructive 3MA technique, which is based on the measurement of electromagnetic properties of the inspected material, should be used for this purpose. Due to the machining process, the material shows a multi-layer structure with different residual stress levels, each characterized by its own electromagnetic properties. In order to simulate signals of the so-called incremental permeability mode of 3MA, the individual electromagnetic properties had to be determined first. For subsequent, FEM methods have been developed, overcoming issues with respect to multi-scale geometry and time, and the local hysteretic behavior identification at every point in the material under investigation. The developed computation strategy and the modeling assumptions are validated by a comparison of the numerical simulations with measurements and shows promising results.

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