Magnetic structures of Zr6CoAs2-type Ho6−xErxMnBi2 solid solutions

Investigations were made by neutron diffraction on Zr6CoAs2-type (space group P6¯2m no. 189) Ho6−xErxMnBi2 solid solutions. The ferromagnetic ordering temperature decreases from Ho6MnBi2 (TC = 200(6) K) to Er6MnBi2 (TC = 100(4) K), whereas temperatures of ferrimagnetic (or antiferrimagnetic) ordering (TFerri and TAFerri) are found to have non-monotonic dependences on the content of Er: TFerri = 58(4) K for Ho6MnBi2, TFerri = 162(4) K for Ho4.5Er1.5MnBi2, TFerri = 150(4) K for Ho3Er3MnBi2, TAFerri = 78(4) K for Ho1.5Er4.5MnBi2 and TAFerri = 52(4) K for Er6MnBi2.In these compounds, no local moment was detected on the manganese ion site, except for Ho1.5Er4.5MnBi2 and Er6MnBi2 compounds. The manganese magnetic moments (μMn) is ∼1.5μB and these are antiferromagnetically coupled with that of rare earth moments.