The magnetic field dependence of the energy of long-wavelength mangons in Tb-10% Ho has been studied by inelastic neutron scattering. The results agree with the "frozen-lattice" model, provided that the second-order magnetoelastic effect is taken into account. The planar anisotropy is almost entirely the result of magnetoelastic effects. The temperature dependences of the anisotropy parameters have been deduced from the results.

• Received 20 January 1970

DOI:https://doi.org/10.1103/PhysRevLett.25.1451