Magnetoelastic coupling and quadrupolar pair interactions in cubic rare-earth intermetallic compounds

Abstract

Magnetoelastic effects are very large in cubic rare-earth intermetallic compounds, especially for the tetragonal and trigonal strain modes. This magnetoelasticity of dominant one-ion origin appears to be the best experimental probe for studying the large quadrupolar pair interactions observed in these compounds. The used Hamiltonian includes the crystalline electric field, the bilinear interactions and the Zeeman coupling with an applied magnetic field, the quadrupolar pair interactions and the magnetoelastic coupling. The free energy is derived using in the non-ordered phase an analytical susceptibility formalism: the anisotropic magnetization and parastriction and the various elastic modes are then deduced. The full coherency of the determinations for both the magnetoelastic coefficients and the quadrupolar pair interactions parameters is demonstrated in TmZn, TmCd and PrPb 3, where a quadrupolar ordering occurs in the paramagnetic phase and is explained in detail.