Experimental synthesis demonstrates extended lanthanum solubility up to twenty percent in bilayer iridates, revealing distinct metallic and magnetic phases under extreme conditions.
Key Points
To overcome ambient-pressure doping constraints in bilayer strontium iridate using high-pressure and high-temperature synthesis to examine electron doping in the Mott state.
Synthesized nominal (Sr1–xLax)3Ir2O7 crystals across nominal concentrations (x = 0.05, 0.10, 0.15, and 0.20) under high-pressure, high-temperature conditions.
Determined crystal structure and elemental composition via single-crystal X-ray diffraction refinements and scanning electron microscopy energy dispersive X-ray spectroscopy.
Evaluated magnetic transitions, hysteresis, and transport behavior to characterize resulting electronic and magnetic phases.
Single-crystal X-ray diffraction confirmed extended lanthanum solubility reaching approximately (Sr0.8La0.2)3Ir2O7 for nominal x = 0.15, before the structure transformed into cubic perovskite Sr1–xLaxIrO3 at nominal x = 0.20.
The nominal x = 0.05 composition exhibited a ferromagnetic-like transition near 186 K with magnetic hysteresis and spin–lattice coupling, maintaining a strongly insulating state despite heavy doping.
The nominal x = 0.15 composition displayed metal-like electrical conduction and weakened magnetic order through carrier delocalization, alongside disorder-induced localization at low temperatures.