Abstract
Magneto-elastic (ME) coupling effects in the simple cubic antiferromagnet RbMnF3 have been studied by observing shifts in antiferromagnetic resonance (AFMR) frequency and changes in AFMR line shape with the application of axial stress. Antiferromagnetic resonance in a two-sublattice antiferromagnet with a general anisotropy and ME interaction is analyzed. Formulas for the evaluation of ME constants of a two-sublattice cubic antiferromagnet are presented. ME constants of RbMnF3 have been determined as a function of temperature from measurements of AFMR in single-crystal specimens under applied stress. The spin-lattice strain coefficients in the spin Hamiltonian for S-state Mn2+ in RbMnF3 have been determined from experimental ME constants and calculated magnetic dipolar ME constants. Large changes in the static and dynamic response of low-anisotropy RbMnF3 can be effected by the application of stress; via ME coupling, applied stress can change both the form and magnitude of the total anisotropy. The measured AFMR linewidth of RbMnF3 at low temperatures is shown to be due to inhomogeneous strain broadening. The intrinsic relaxation linewidth is estimated to be less than 5 Oe. © 1967 The American Physical Society.