Equilibrium Spin Configuration and Antiferromagnetic Resonance of KMnF₃ at the Low Temperature Phase

Abstract

The antiferromagnetic resonance of KMnF 3 at helium temperature has been studied. The equilibrium orientation of magnetic sublattices and the resonance frequencies are calculated from the free energy expression which involves antisymmetric exchange energy and orthorhombic and cubic anisotropy energies. The Dzyaloshinsky-Moriya vector is taken along the b -axis ([\bar110] in the pseudocubic cell). The experimental results are in good agreement with the theory. In the absence of the applied field, the sublattice magnetizations are in the b -plane, making 43.4° with the c -axis ([001]).