Developing rare-earth-free permanent magnets with competitive magnetic performance is a necessary step forward to enable an ecological transition based on clean energy generation and green mobility (wind turbines, e-vehicles). Our research group has recently patented a novel cold sintering method for fabricating rare-earth-free hexaferrite-based magnets, which allows reducing sintering temperature, and in turn, lowering the energy consumption in >30% compared to the sintering methods used in industry. We intend to replicate this process in a diamond anvil cell (DAC) and follow it in situ based on time-resolved X-ray absorption spectroscopy (XAS) measurements, with the aim of: (i) gaining a deeper understanding of the process itself and of the various phase changes undergone, (ii) refining the preparation method to better control the produced material, ideally further reducing the sintering temperature.