Probing Ice-Rule-Breaking Transition in Dy_{2}Ti_{2}O_{7} Thin Film by Proximitized Transport and Magnetic Torque

While the spin-ice state of bulk pyrochlores such as Dy_{2}Ti_{2}O_{7} and Ho_{2}Ti_{2}O_{7} has been extensively studied in the past several decades due to its unique degenerate ground state and emergent monopole excitation, whether it survives in the thin-film form remains a mystery. The limited volume of the thin-film sample makes it challenging to study the intrinsic magnetic properties. Here, we synthesized 18-nm-thick Dy_{2}Ti_{2}O_{7} thin film on yttria-stabilized zirconia with 9.5  mol% Y_{2}O_{3} substrate and capped it by a thin conductive Bi_{2}Ir_{2}O_{7} layer and performed the proximitized magnetoresistance measurements. Our Letter found that the ice-rule-breaking phase transition survives but with a modified effective nearest-neighbor interaction (J_{eff}=1.054  K) and distorted Ising spin axes (ε=+0.051) compared to the bulk crystal. The results are supported by the simultaneously measured capacitive torque magnetometry. Our Letter demonstrates that proximitized transport is an effective tool for thin films of insulating frustrated magnets.