High-Magnetic-Field Thermal Expansion And Elastic Properties Of Cerhin5

We report high-magnetic-field thermal expansion and magnetostriction results on CeRhIn5 single crystals. Several phase transitions, both first and second order, are observed when the field is applied perpendicular to the crystallographic c axis. The magnetic field dependence of the thermal-expansion coefficient above 15 K, where the magnetic correlations are negligible, can be explained supposing an almost pure vertical bar +/- 5/2 > ground state doublet, in apparent contradiction with neutron scattering experiments. Although the spin-lattice interaction is relevant in this compound, the effect of the magnetic correlations on the elastic properties is relatively weak, as revealed by resonant ultrasound spectroscopy experiments.