Abstract
Neutron scattering measurements on the pyrochlore magnet Ce2Zr2O7 reveal an unusual crystal field splitting of its lowest J=5/2 multiplet, such that its ground-state doublet is composed of mJ=±3/2, giving these doublets a dipole-octupole (DO) character with local Ising anisotropy. Its magnetic susceptibility shows weak antiferromagnetic correlations with θCW=−0.4(2) K, leading to a naive expectation of an all-in, all-out ordered state at low temperatures. Instead, our low-energy inelastic neutron scattering measurements show a dynamic quantum spin ice state, with suppressed scattering near |Q|=0, and no long-range order at low temperatures. This is consistent with recent theory predicting symmetry-enriched U(1) quantum spin liquids for such DO doublets decorating the pyrochlore lattice. Finally, we show that disorder, especially oxidation of powder samples, is important in Ce2Zr2O7 and could play an important role in the low-temperature behavior of this material.
