Molten salt synthesis of Mn-based antiperovskite nanoparticles with tunable magnetic properties

Mn-based antiperovskite nanoparticles hold promise for magnetic applications, but synthesis has been confined to high-temperature solid-state methods impeding nanoscale control. Here, a NaCl/KCl molten salt flux produces highly crystalline Mn 3 ZnC, Mn 3 AlC, and Mn 3 Zn(C,N) nanoparticles (10–30 nm) at 900 °C within 6 h. XRD and HRTEM confirm the cubic Pm̅3m symmetry and systematic lattice contraction upon nitrogen substitution. The compositions span a broad magnetic spectrum, Mn 3 ZnC is superparamagnetic (M s  = 27.87 emu/g, H c  = 1.4 Oe, T C  = 120 °C), Mn 3 Zn(C,N) is soft ferromagnetic (21.88 emu/g, 69.3 Oe, T C  = 142 °C), and Mn 3 AlC exhibits harder magnetic behavior (12.95 emu/g, 333.7 Oe). Under alternating magnetic fields, Mn 3 Zn(C,N) achieves a specific absorption rate of 15.10 W/g, showing that intermediate coercivity, tuned by interstitial nitrogen, optimizes hysteresis-loss heating in earth-abundant antiperovskites.