Ordered magnetic frustration: XV. Re-examination of the magnetic structure of α-KCrF4

Abstract The magnetic structure of α-KCrF 4 , presented in a previous article of this series is re-examined. It appears that, due to the pseudosymmetry of the crystal cell, two magnetic models are quasi-equivalent. Although these models are impossible to differentiate from magnetic neutron diffraction only, a detailed examination of the superexchange configuration allows one to discriminate in favor of the new model without any ambiguity. As a consequence, the frustrated magnetic structure of α-KCrF 4 allows one to derive the dependence of the coupling constants via superexchange path Cr 3+ -F - -Cr 3+ on the superexchange angle θ, namely J θ / J 180° = -0.69+1.69 cos 2 θ.