Anisotropic magnetocaloric properties of the ludwigite single crystal Cu2MnBO5

We report upon the specific heat and magnetocaloric properties of Cu₂MnBO₅ over a temperature range of 60-350 K and in magnetic fields up to 18 kOe. It is found that at temperatures below the Curie temperature (T_C ∼ 92 K), C_P(T)/T possesses a linear temperature-dependent behavior, which is associated with the predominance of two-dimensional antiferromagnetic interactions of magnons. The temperature independence of C_P/T = f(T) is observed in the temperature range of 95-160 K, which can be attributed to the excitation of the Wigner glass phase. The magnetocaloric effect [i.e., the adiabatic temperature change, ΔT_ad (T,H)] is assessed through a direct measurement or an indirect method using the C_P(T,H) data. Owing to its strong magnetocrystalline anisotropy, an anisotropic magnetocaloric effect (MCE) or the rotating MCE [ΔT_ad^rot (T)] is observed in Cu₂MnBO₅. A deep minimum in the ΔT_ad^rot (T) near the T_C is observed and ascribed to the anisotropy of the paramagnetic susceptibility.