Quadrupolar susceptibility and magnetic phase diagram of PrNi₂Cd₂₀ with non-Kramers doublet ground state

ABSTRACT

In this study, ultrasonic measurements were performed on a single crystal of cubic PrNi₂Cd₂₀, 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 (C₁₁−C₁₂)/2, which is related to the Γ₃-symmetry quadrupolar response, exhibits the Curie-type softening at temperatures below ∼30 K, which indicates that the present system has a Γ₃ non-Kramers doublet ground state. A leveling-off of the elastic response appears below ∼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 Γ₃-symmetry multipoles. A magnetic field–temperature phase diagram of the present compound is constructed up to 28 T for H || [110]. A clear acoustic de Haas–van Alphen signal and a possible magnetic-field-induced phase transition at H ∼26 T are also detected by high-magnetic-field measurements.

KEYWORDS:

• Elasticity
• ultrasonic attenuation
• strongly correlated electrons
• phase diagrams
• crystal field
• Kondo effect

Acknowledgements

One of the authors (T.Y.) would like to express profound respect for Prof. M. Brian Maple’s brilliant achievements that opened the gates to the fertile world of research on cage-structured compounds and the related SCES phenomena originating from research on the filled-skutterudite systems. Research studies at UC San Diego were supported by the US NSF DMR-1810310 and the US DOE under grant number DE-FG02-04-ER46105. Research studies at Hokkaido University and HZDR were supported by JSPS KAKENHI Grant Nos. 26400342, JP18H04297, JP17K05525, JP18KK0078, JP15H05882, JP15H05885, JP15K21732, and JP19H01832 and the Strategic Young Researcher Overseas Visits Program for Accelerating Brain Circulation. We acknowledge support from the DFG through the Würzburg-Dresden Cluster of Excellence on Complexity and Topology in Quantum Matter, ct.qmat (EXC 2147, project-id 39085490), and from the HLD at HZDR, member of the European Magnetic Field Laboratory (EMFL). This work was also partly supported by the High Field Laboratory for Superconducting Materials, Institute for Materials Research, Tohoku University.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Tatsuya Yanagisawa http://orcid.org/0000-0003-4558-8824

Additional information

Funding

This work was supported by Division of Materials Research: [Grant Number DMR-1206553]; Japan Society for the Promotion of Science: [Grant Number 26400342, JP15H05882, JP15H05885, JP15K21732, JP17K05525, JP18H04297, JP18KK0078, JP19H01832]; U.S. Department of Energy: [Grant Number DE-FG02-04-ER46105].