Candidate quantum spin ice in the pyrochlore Pr${}_2$Hf${}_2$O${}_7$

Abstract

We report the low temperature magnetic properties of the pyrochlore Pr${}_2$Hf${}_2$O${}_7$. Polycrystalline and single-crystal samples are investigated using time-of-flight neutron spectroscopy and macroscopic measurements, respectively. The crystal-field splitting produces a non-Kramers doublet ground state for Pr${}^{3+}$, with Ising-like anisotropy. Below 0.5 K ferromagnetic correlations develop, which suggests that the system enters a spin ice-like state associated with the metamagnetic behavior observed at $\hat{I}{¼}_0{H}_c\sim 2.4$~T. In this regime, the development of a discrete inelastic excitation in the neutron spectra indicates the appearance of spin dynamics which are likely related to cooperative quantum fluctuations.

7 pages, 5 figures, 1 table