Magneto-optical Kerr microscope with in situ tension-compression stage

• Subject Area: Materials Engineering
• Term: Funded in 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 464498574

The requested Kerr microscope offers a wide range of application possibilities in interdisciplinary research activities with regard to the investigation of magnetic domain structures, their distribution and their behavior in dependence of magnetization, mechanical stresses and temperature. The focus is on the characterization of the local micro-magnetic characteristics of ferromagnetic construction materials caused by mechanical stress and temperature.The Kerr microscope system is a high-tech light microscope using the magneto-optical Kerr effect as contrast mechanism for the visualization of magnetic domains and magnetization processes. The system will be mainly applied for exploring the microstructure-dependent mechanisms of magnetization in order to characterize material behavior under elastic stresses. Although most construction materials are operated under low load stresses far below the yield strength, an accurate characterization of material response is very limited by a lack of information about the mechanisms preceding a plastic deformation. Based on the analysis of magnetic parameter of ferromagnetic materials, it is possible to quantify the response of material and of the operationally relevant microstructural changes even at low mechanical stress. The novel experimental configuration of the proposed Kerr microscope allows a high-resolution light-microscopic characterization of the magnetic domains of ferromagnetic construction materials as well as the movement of the domain walls by applying of an external magnetic field, mechanical stresses and temperature. The aim of the research activities is to create new basis for observation, description and determination of mechanisms of material behavior in order to explore latest scientific issues in materials science and engineering. The microscope will also be applied in research projects for in situ investigation on composite materials and light metals. All current research projects of applicant on deformation behavior necessary include in situ mechanical testing by means of scanning electron microscopy and computer tomography. The phase contrast of light microscopy allows simultaneous microstructure analysis as well as observation of the crack propagation closing the gap in multiscale in situ characterization of deformation and failure mechanisms.It is expected, that the proposed device configuration of the Kerr microscope will provide new dimension in understanding of elastic behavior of ferromagnetic materials as well as deformation behavior of composites and light metals. Therefore, the novel Kerr microscope will generate a significant insight that will contribute to a fundamental understanding of the material behavior especially under low stresses, explored in situ with highest scientific precision.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Magnetoptisches Kerr-Mikroskop mit in-situ Zug-Druck-Modul
• Instrumentation Group: 5000 Labormikroskope
• Applicant Institution: Technische Universität Dortmund
• Leader: Professor Dr.-Ing. Frank Walther