Magnetization and magnetostriction measurements of the dipole-octupole quantum spin ice candidate Ce2Hf2O7

We investigate the magnetization and the magnetostriction of the dipole-octupole quantum spin ice candidate Ce2Hf2O7 down to 50 mK. We find that the magnetization curves observed with the magnetic field applied along all the principal axes ([100], [110], and [111]) exhibit a magnetic hysteresis below around 300 mK. In addition, a kink-like feature is observed in the magnetization under B || [111], at which the magnetostriction also shows a convex field dependence. Our classical Monte-Carlo and quantum exact diagonalization calculations demonstrate that these features in the magnetization are well reproduced by the spin Hamiltonian with a dominant interaction between the octupole moments and with a QSI ground state, indicating the emergence of a dipole-octupole QSI in this compound.