The Tb-Co-Ga system at 870 K as a representative of rare-earth cobalt gallides: Crystal structure and magnetic properties

摘要

The Tb-Co-Ga system has been investigated at 870 K by X-ray powder and microprobe elemental analyses. The existence of the known compounds TbGo(5)Ga(7) (ScFe6Ga6-type), Tb2Co3Ga9 (Y2Co3Ga9-type), TbCoGa5 (HoCoGa5-type), (TbCo7Ga21)-Co-6 (Ho6Co7Ga21-type), Tb4Co3Ga16 (Sm4Co3Ga16-type), Tb2CoGa8 (Ho2FeGa8-type), TbCo3-2.8Ga2-2.2 (HoNi2.6Ga2.4-type), Tb3Co7 similar to 5.4Ga2 similar to 3.6 (CeNi3-type), TbCo1 similar to 1.67Ga1 similar to 0.33 (TiNiSi-type), Tb2CoGa3 (Lu2CoGa3-type), Tb3Co3Ga (W3CoB3-type), Tb2Co2Ga (Mo2NiB2-type) and Tb6Co2 similar to 2.2Ga1 similar to 0.8 (Ho6Co2Ga-type) has been confirmed, the TbCo6.Ga-7-5.5(0.3-1.5) (TbCu7-type) is suggested, meanwhile new MgZn2-tyPe TbCo1.33Ga0.67, Er12Ni8Ga3-type Tb12Co5 similar to 5.5Ga3 similar to 2.8 and Sm26Co11Ga6-type Tb26Co8 similar to 9.4Ga12 similar to 7.6 were detected at 870 K. Quasi-binary solid solutions were detected for Tb2Co17, TbCo8, Tb2Co7, TbCo3, TbCo2, TbGa2 and Tb5Ga3 at 870, while no appreciable solubility was observed for the other binary compounds in the Tb-Co-Ga system. Magnetic properties of the Tb4Co3Ga16, Tb2CoGa3, Tb3Co7Ga2, Tb3Co8Ga and Tb26Co9.4Ga7.6 compounds have been studied this work. Tb4Co3Ga16 is antiferromagnetic, while Tb2CoGa3, Tb3Co7Ga2, Tb3Co8Ga and Tb26Co9.4Ga7.6 exhibit mixed ferro-antiferromagnetic ordering. Additionally, new Er26Ni8Ga3-type {Dy, Ho}(12)Co5.5Ga2.5, Sm26Co11Ga6-type Gd26Co9.2Ga7.8, Dy26Co8Ga9, Er26Co8Ga12 compounds and Cr5Ga3-type Dy8Co0.9Ga2.1 quasi-binary solid solution have been detected in this work.