Magnetic structures of the anisotropic intermetallic compounds Er 2 CoGa 8 and Tm 2 CoGa 8

摘要: Two members of the isostructural ${R}_{2}{\text{CoGa}}_{8}$ intermetallic series, ${\text{Er}}_{2}{\text{CoGa}}_{8}$ and ${\text{Tm}}_{2}{\text{CoGa}}_{8}$, have been studied by powder neutron diffraction. Antiferromagnetic ordering rare-earth sublattices was confirmed to occur at 3.0 K 2.0 K, respectively. Furthermore, determination critical exponent showed adopt a three-dimensional universality class. In spite common magnetic easy axis similar structural characteristics, antiferromagnetic structures were found be different for erbium- thulium-based compounds. The corresponding space groups determined ${P}_{2a}mm{m}^{\ensuremath{'}}$ ${P}_{C}mmm$. difference in is discussed based on crystal electric field effects that are known prevalent such materials.