Longitudinal magneto-optical Kerr effect (MOKE) magnetometry integrated within synchrotron-based diffraction for in...

We report the development and synchrotron integration of a longitudinal magneto-optical Kerr effect (MOKE) magnetometer designed for in situ operation during x-ray diffraction (XRD) experiments under multiaxial mechanical loading. The optical layout, magnetic-field geometry, and mechanical compatibility were optimized to enable synchronized acquisition of MOKE hysteresis loops, XRD lattice strain, and digital image correlation (DIC) data within the constrained environment of a diffraction goniometer. The capabilities of the platform are demonstrated on a Co/W thin film deposited on a flexible Kapton® substrate subjected to equi-biaxial tensile loading. The combined MOKE-XRD-DIC measurements reveal three distinct mechanical regimes from elastic strain transfer to partial relaxation and ultimately full mechanical fragmentation, each associated with a characteristic magnetic response. Post-mortem image analysis provides a quantitative description of fragment morphology, linking crack topology to the evolution of magnetic properties and highlighting the role of fragment size, shape anisotropy, and mechanical isolation in strain-dependent magnetic behavior. The present approach establishes a multi-scale framework that integrates surface magnetometry, structural probes, and real-space imaging, opening new opportunities for studying magneto-mechanical coupling and damage-driven functional evolution in flexible magnetic thin films.