Kinetically Stabilized 4 f –5 d Pyrochlore Thin Films: A Route to Magnetic Fragmentation

Abstract

Magnetic fragmentation in 4f–5d pyrochlores, such as Ho2Ir2O7, offers a route to monopole-driven physics, but translating this physics into thin-film form remains a severe synthesis problem. The challenge is to crystallize the pyrochlore phase by creating a metastable precursor that preserves iridium chemistry within a narrow kinetic window. Here we identify plume thermalization as the key synthesis variable that controls this metastable pathway. In pulsed-laser deposition followed by in situ solid-phase epitaxy (SPE), xenon, the heaviest stable noble gas, mass-selectively governs plume kinetics and produces an atomically flat metastable amorphous precursor with uniform Ho/Ir chemistry. Structural probes and X-ray photoelectron spectroscopy confirm that this precursor retains local pyrochlore connectivity without long-range translational order. The SPE-stabilized crystalline films are single-phase, [111]-oriented, electrically conductive, and magnetically active. Mass-selective plume control can open the narrow kinetic window required to synthesize and explore new magnetic pyrochlore materials.