Quadrupolar Susceptibility and Magnetic Phase Diagram of PrNi${}_2$Cd${}_{20}$ with Non-Kramers Doublet Ground State

Abstract

In this study, ultrasonic measurements were performed on a single crystal of cubic PrNi${}_2$Cd${}_{20}$, down to a temperature of 0.02 K, to investigate the crystalline electric field ground state and search for possible phase transitions at low temperatures. The elastic constant $(C_{11}-C_{12})/2$, which is related to the $\hat{I}{“}_3$-symmetry quadrupolar response, exhibits the Curie-type softening at temperatures below $\sim$30 K, which indicates that the present system has a $\hat{I}{“}_3$ non-Kramers doublet ground state. A leveling-off of the elastic response appears below $\sim$0.1 K toward the lowest temperatures, which implies the presence of level splitting owing to a long-range order in a finite-volume fraction associated with $\hat{I}{“}_3$-symmetry multipoles. A magnetic field-temperature phase diagram of the present compound is constructed up to 28 T for $H\parallel$ [110]. A clear acoustic de Haas-van Alphen signal and a possible magnetic-field-induced phase transition at $H\sim$26 T are also detected by high-magnetic-field measurements.

13 pages, 7 figures