Acoustic signatures of the phase transitions in the antiferromagnet U2Rh2Sn

Abstract

We report on ultrasound measurements in a single crystal of the antiferromagnet U 2 Rh 2 Sn as a function of temperature and magnetic field. We find pronounced anomalies in the sound velocity at the Néel temperature, 25 K, and at the field-induced spin-flop-like transition at 22.5 T, which points to a strong magnetoelastic coupling. Additionally, we find that in the paramagnetic regime the temperature dependence of the magnetic susceptibility and the field dependences of the magnetization and sound velocity of transverse acoustic waves can be well described assuming a localized character of the 5 f electrons. Using this premise, the crystal-electric-field scheme of U 2 Rh 2 Sn has been determined.

Magnetic transition due to the inter-singlet spin-exchange interaction and elastic softening by the interplay of electric quadrupoles in the distorted kagome lattice antiferromagnet Tb3Ru4Al12

“…Here, the transverse modulus C 66 (C 44 ) is the linear responses to the ε xy and ε xx − ε yy (ε yz and ε zx ) strains which couple to the quadrupoles O xy and O 2 2 (O yz and O zx ), respectively, in the hexagonal symmetry. The CEF analyses based on the elastic properties in addition to the magnetic properties make the results more precise [20,22,24,33,34,36]. In this work, to clarify the 4 f -electronic state under the CEF and an influence of the quadrupole interaction in Tb 3 Ru 4 Al 12 , we measured the elastic moduli using ultrasonic technique at zero magnetic field and under fields, and determined the CEF level scheme and the H-T phase diagrams.…”