Highly Anisotropic Magnetism and Nearly Isotropic Magnetocaloric Effect in Mn₃Sn₂ Single Crystals

Mn₃Sn₂ has been proposed as an ideal material for magnetic refrigeration. It undergoes two successive ferromagnetic transitions (T_C1 = 262 K and T_C2 = 227 K) and one antiferromagnetic transition (T_N = 192 K). Herein we report, for the first time, the preparation of single crystals of Mn₃Sn₂ from Bi flux. The resultant anisotropic magnetic properties and magnetocaloric effect are investigated along the three principal crystallographic directions of the crystal. Significant anisotropy of magnetic susceptibility and multiple field-induced metamagnetic transitions were found at low fields, whereas the magnetocaloric effect was found to be almost isotropic and larger than that of the polycrystalline one. The maximum magnetic entropy change amounts to −ΔS_M = 4.01 J⋅kg⁻¹⋅K⁻¹ near T_C1 under a magnetic field change of μ₀ΔH = 5 T along the c-axis, with the corresponding refrigerant capacity of 1750 mJ⋅cm⁻³. Combined with a much wider cooling temperature span (∼ 80 K), our results demonstrate Mn₃Sn₂ single crystal to be an attractive candidate working material for active magnetic refrigeration at low temperatures.