Experimental Study of the Dipolar-Octupolar Pyrochlore Quantum Spin Liquid Candidate Ce₂Hf₂O₇

We present new experimental results on powder and single crystal samples of the new magnetic pyrochlore Ce₂Hf₂O₇. High-energy neutron spectroscopy confirms a dipole-octupole crystal electric field ground state for this rare-earth pyrochlore magnet, consistent with previous measurements and corresponding to two components of pseudospin-1/2 transforming as dipoles and the other component transforming as an octupole. Higher energy-resolution neutron spectroscopy and neutron diffraction show a disordered ground state, which is also consistent with magnetic susceptibility and heat capacity measurements.