thin films

The pyrochlore iridates are a class of candidate materials for the topological Weyl semimetal, which can host hidden topological and magnetic phases in the thin film form. To investigate the intrinsic properties relevant to the Ir sublattices, we fabricated high-quality epitaxial (111)-oriented pyrochlore Eu₂Ir₂O₇ thin films on YSZ substrates, in which the Eu³⁺ ions are magnetically silent. Temperature-dependent transport reveals an onset of the metal-insulator transition at T_C around 110 K, similar to the bulk value. However, magneto-transport measurements reveal that below T_C in the insulating phase with the non-colinear all-in-all-out antiferromagnetic order, a distinct anomalous Hall effect (AHE) emerges combined with a butterfly-shape hysteretic magnetoresistance. The AHE gets strongly pronounced at lower temperatures, with colossal enhancement of both the saturation field H_S and the coercivity H_C. These findings are signatures of the emergent interacting topological phases in thin films of [111]-oriented pyrochlore iridates.