SmCo5型中熵、高熵金属间化合物的结构与磁性

以SmCo₅为原型，设计了3种中熵金属间化合物(Sm_1/3Ce_1/3Pr_1/3)Co₅、(Sm_1/3Ce_1/3Nd_1/3)Co₅、(Sm_1/3Pr_1/3Nd_1/3)Co₅和1种高熵金属间化合物(Sm_1/4Ce_1/4Pr_1/4Nd_1/4)Co₅，并采用原子半径差和混合焓预测了形成单相结构的可能性. 应用真空电弧熔炼技术成功制备了4种金属间化合物. 采用X射线衍射仪(XRD)、能谱仪(EDS) 和振动样品磁强计(VSM) 表征了样品的物相、成分和磁学性能. 结果表明:4种化合物均为单相，具有六方CaCu₅结构，空间群为P6/mmm，稀土原子占据1a位置；稀土位置上的原子浓度为等原子比；化合物的室温磁化行为遵循Langevin模型，磁化强度依赖于化合物的成分；磁价模型计算证实了化合物(Sm_1/3Ce_1/3Pr_1/3)Co₅、(Sm_1/3Ce_1/3Nd_1/3)Co₅和(Sm_1/4Ce_1/4Pr_1/4Nd_1/4)Co₅中的Ce为+4价，对磁矩没有贡献.

The Structure and Magnetic Properties of SmCo5-type Medium- and High-entropy Intermetallic Compounds

Three medium-entropy intermetallic compounds (Sm_1/3Ce_1/3Pr_1/3)Co₅, (Sm_1/3Ce_1/3Nd_1/3)Co₅ and (Sm_1/3Pr_1/3Nd_1/3)Co₅ and a high-entropy intermetallic compound (Sm_1/4Ce_1/4Pr_1/4Nd_1/4)Co₅ were designed on the basis of SmCo₅. The possibility of forming single-phase structure was predicted using atomic size difference and mixing enthalpy. Four intermetallics were synthesized via the vacuum arc-melting technology. The X-ray diffractometer (XRD), the energy dispersive X-ray spectrometer (EDS) and the vibration sample magnetometer (VSM) were used to study the phase, chemical compositions and magnetic properties. The results show that four intermetallics are single-phase structures and crystalline in a hexagonal CaCu₅ structure with a space group of P6/mmm. The rare earth atoms occupy 1a site. The atomic concentration at the rare earth site is equiatomic ratio. The room temperature magnetizations follow the Langevin model. Magnetization depends on the composition of the compound. The magnetic valence model was employed to check the valence of Ce. The calculated results show that Ce is tetravalent in (Sm_1/3Ce_1/3Pr_1/3)Co₅, (Sm_1/3Ce_1/3Nd_1/3)Co₅ and (Sm_1/4Ce_1/4Pr_1/4Nd_1/4)Co₅ and makes no contribution to the magnetic moment.