Engineering a Galinstan-based ferromagnetic fluid for heat management

• Magnetic Ni microparticles were successfully embedded in a Galinstan matrix. • Thorough characterization unveils synergetic high thermal conductivity and magnetism. • The fluid applicability was tested in a magnetically actuated thermal switch system. • During the MATS operation, a maximum temperature span of 19.8 % was achieved. • First demonstration of a Galinstan-based ferromagnetic fluid for magnetically actuated TCDs. The development of increasingly smaller electronic devices brings on heat dissipation challenges, which can severely hinder their performance. Consequently, there is a critical need to maintain the working temperature of these devices at optimal values. At room temperature, the versatile design and adaptability of fluidic thermal switches makes them an auspicious solution. In this work, the large heat conductivity and magnetic material compatibility of Galinstan motivated the production of a novel ferromagnetic fluid. Through mechanical alloying within an inert atmosphere, we embedded Ni microparticles in a Galinstan matrix, which provided a liquid metal with a ferromagnetic behavior. This fluid is suitable for a wide range of applications in thermal management. Here, we experimentally demonstrate that a Galinstan-based mixture containing 2 . 6 wt% of Ni can serve as heat exchange medium in a magnetically activated fluidic thermal switch device. This mixture establishes an optimal thermal bridge between heat source and sink, enabling heat dissipation from the source. This effect intensifies with the device operating frequency, reaching a maximum temperature span of 19 . 8 % and a maximum switching ratio of 1.26 . These results demonstrate the potential of the developed fluid to be integrated into fluidic technologies for temperature control of electronic components.