COUPLED ANTIFERROMAGNETIC-NUCLEAR-MAGNETIC RESONANCE IN RBMNF3

The coupling between antiferromagnetic and Mn55 nuclear resonances in RbMnF3 has been studied both theoretically and experimentally. The electronic and nuclear frequencies have been derived by solving the coupled equations of motion for (a) a four-sublattice model, consisting of two electronic and two nuclear magnetic sublattices; (b) a two-sublattice model in which the electron-nuclear interaction is represented by a static anisotropy field. For the electronic modes, the differences in the frequencies obtained from the two models are negligible. However, only the four-sublattice theory predicts the NMR frequencies to good accuracy, for applied fields both greater and less than the spin-flop value. The temperature dependence of the crystal parameters has been included, and comparison is made between theory and experiment in the temperature range where the parallel susceptibility is significant. © 1969 The American Physical Society.