Density functional analysis of the magnetic structures of Sr2MGe2O7 (M=Mn, Co)

Abstract To examine the difference between the magnetic structures of Sr2MGe2O7 (M=Mn, Co), we evaluated their spin exchange interactions by performing energy-mapping analysis based on density functional theory calculations. The calculated intra- and inter-layer spin exchanges correctly predict the G-type and C-type antiferromagnetic structures of Sr2MnGe2O7 and Sr2CoGe2O7, respectively, and the Curie–Weiss temperatures estimated from these spin exchanges are also in good agreement with the experiment. The ∥c and ⊥c orientations of the spins in the ordered magnetic structures of Sr2MnGe2O7 and Sr2CoGe2O7, respectively, were also examined by considering spin–orbit coupling.