A new macroscopically degenerate ground state in the spin ice compound Dy₂Ti₂O₇under a magnetic field

Abstract

The low temperature magnetic properties of pyrochlore compound Dy2Ti2O7 in\nmagnetic fields applied along the [111] direction are reported. Below 1 K, a\nclear plateau has been observed in the magnetization process in the field range\n2~9 kOe, followed by a sharp moment jump at around 10 kOe that corresponds to a\nbreaking of the spin ice state. We found that the plateau state is disordered\nwith the residual entropy of nearly half the value of the zero-field state,\nwhose macroscopic degeneracy comes from a frustration of the spins on the\nkagome layers perpendicular to the magnetic field.\n