Anisotropic magnetocaloric properties of the ludwigite single crystal Cu2MnBO5

Abstract

We report upon the specific heat and magnetocaloric properties of Cu2MnBO5 over a temperature range of 60-350K and in magnetic fields up to 18kOe. It is found that at temperatures below the Curie temperature (T-C similar to 92K), 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 95-160K, which can be attributed to the excitation of the Wigner glass phase. The magnetocaloric effect [i.e., the adiabatic temperature change, Delta T-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 [Delta T-ad(rot) (T)] is observed in Cu2MnBO5. A deep minimum in the Delta T-ad(rot) (T) near the T-C is observed and ascribed to the anisotropy of the paramagnetic susceptibility.