通过结构和磁性测量,研究了四元哈斯勒合金Ni50-xCoxMn38Sn12(x=1,2,4,6,8)的晶体结构和相变特征.结果表明,Co原子的掺杂不但没有影响三元哈斯勒合金Ni-Mn-Sn的原有结构,而且还增强了样品在奥氏体相的铁磁交换作用.此外,通过Maxwell方程计算了其中三种成分样品(x=2,4,6)的磁熵变ΔSM,在磁场改变50kOe情况下,获得了Ni46Co2Mn38Sn12样品在320K附近约37.09J/kgK的磁熵变.
The crystal structure and phase transition in Ni_50-xCo_xMn_38Sn_12(x=1, 2, 4, 6, 8) Heusle alloys were investigated by means of structure analysis and magnetism measurements. The results show that the doping of the Co atom affects neither the original structure of Ni-Mn-Sn Heusler alloys, nor the ferromagnetic interaction strengthens in the austenitic state. Furthermore, based on Maxwell equation, the magnetic entropy change (ΔS_M) of three samples (x=2, 4, 6) has been calculated. A large magnetic entropy change of 37.09 J/kg K at about 320 K for a magnetic field change of 50 kOe is obtained in Ni_48Co_2Mn_38Sn_12 alloy.