The first part of the work deals with the detailed investigation of ferromagnetic Th1Mn12-phases in the material systems Sm-Fe-Mo-Al and Ce-Sm-Fe-Ti-V. Different methods were employed to characterize existence ranges as well as magnetic and structural properties. Based on the obtained results, the suitability and potential of these phases for the use in future permanent magnets is discussed. Specifically for the promising Ce0.5Sm0.5Fe10Ti1V1(Ga)-phase, bulk magnets were successfully produced by hot-pressing and subsequent die-upsetting. The samples were characterized in detail, both, magnetically and structurally. The possibility of inducing a texture by die-upsetting was closely investigated and evaluated regarding the factors which are considered to be crucial in the case of Nd-Fe-B-magnets.

In the second part, Kerr microscopy was performed on a set of very different and well-reported permanent-magnetic phases. The magnetic patterns, visualized by polarized light microscopy, were evaluated quantitatively with image processing software and further compared to the respective intrinsic magnetic properties. The potential to quantify the magnetic properties of new ferromagnetic phases based on their domain contrast is assessed. There is a certain compositional sensitivity and the suitability to quickly check for uniaxial anisotropy or substantial polarization. However, quantification remains problematic because the influence of the local chemistry and physics (especially the reduced magnetizations) on the sample surface, regarding the rotation of the polarization plane, is obscure and furthermore overlain by measurement uncertainties.

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