Physical properties of the candidate quantum spin ice system Pr2Hf2O7

Physical properties of a pyrohafnate compound Pr2Hf2O7 have been investigated by ac magnetic susceptibility amp; 967;ac T , dc magnetic susceptibility amp; 967; T , isothermal magnetization M H , and heat capacity Cp T measurements on polycrystalline as well as single crystal samples combined with high resolution synchrotron x ray diffraction XRD for structural characterization and inelastic neutron scattering INS to determine the crystal field energy level scheme and wave functions. Synchrotron XRD data confirm the ordered cubic pyrochlore Fd 3m structure without any noticeable site mixing or oxygen deficiency. No clear evidence of long range magnetic ordering is observed down to 90 mK, however the amp; 967;ac T evinces slow spin dynamics revealed by a frequency dependent broad peak associated with spin freezing. The INS data reveal the expected five well defined magnetic excitations due to crystal field splitting of the J 4 ground state multiplet of the Pr3 . The crystal field parameters and ground state wave function of Pr3 have been determined. The Ising anisotropic nature of the magnetic ground state is inferred from the INS as well as amp; 967; T and M H data. Together these properties make Pr2Hf2O7 a candidate compound for quantum spin ice behavio