Two-dimensional hexagonal boron nitride-ferrofluid hybrids enable efficient magnetic cooling

Abstract

Overheating remains a critical limitation in high-performance electronic and computing systems, necessitating the development of efficient thermal management fluids. In this work, a magnetically responsive hybrid ferrofluid was developed by incorporating two-dimensional hexagonal boron nitride (2D-hBN) nanosheets into a Mn–Zn–ferrite-based ferrofluid. The hybrid system retains magnetic responsiveness while leveraging the high in-plane thermal conductivity and chemical stability of 2D-hBN nanosheets. Structural, spectroscopic, and magnetic characterizations confirm the successful incorporation of 2D-hBN within the ferrofluid without compromising the magnetic functionality of the ferrite nanoparticles. The thermal conductivity of the hybrid fluid increased from 0.294 to 0.582 W m⁻¹ K⁻¹, representing nearly a twofold enhancement compared to the base ferrofluid. Cooling experiments performed under different magnetic field strengths demonstrate field-dependent thermal performance. At an applied magnetic field of 0.30 Tesla, the hybrid ferrofluid achieved a maximum temperature drop of ∼35 °C, corresponding to more than 50% improvement in cooling efficiency compared to the base ferrofluid under identical heat load conditions. These results highlight the potential of 2D-hBN-modified ferrofluids as promising magnetothermal cooling media for passive and magnetically assisted thermal management applications in next-generation electronic systems.