Extending the La Solubility Limit in Sr3Ir2O7 through High-Pressure High-Temperature Synthesis
Abstract
La-doped bilayer iridates provide an important platform for studying the evolution of the spin-orbit-assisted Mott state under electron doping, but the La solubility achieved by conventional ambient-pressure synthesis is limited. Here, we report the synthesis and physical properties of nominally La-doped (Sr1−xLax)3Ir2O7 (x = 0.05, 0.10, 0.15, and 0.20) prepared using high-pressure high-temperature techniques. Single-crystal X-ray diffraction refinements, supported by scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX), reveal significantly enhanced La incorporation, with nominal x = 0.05 and 0.15 corresponding to actual compositions of approximately (Sr0.89La0.11)3Ir2O7 and (Sr0.77La0.23)3Ir2O7, respectively. At nominal x = 0.20, the bilayer phase is no longer stabilized and instead transforms into cubic perovskite Sr1−xLaxIrO3. (Sr0.89La0.11)3Ir2O7 exhibits a ferromagnetic-like transition near 186 K accompanied by magnetic hysteresis and subtle lattice anomalies indicative of spin-lattice coupling. Despite its high electron-doping level, the compound remains strongly insulating, consistent with a heavily doped localized magnetic insulating state distinct from both parent Sr3Ir2O7 and ambient-pressure La-doped samples. In contrast, (Sr0.77La0.23)3Ir2O7 displays metal-like electronic behavior, weakened magnetic order, and enhanced carrier delocalization, although disorder-driven localization persists at low temperatures. These results demonstrate that high-pressure synthesis substantially extends the accessible doping range of bilayer iridates and reveals electronic and magnetic states inaccessible through conventional synthesis routes.
Versions
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BibTeX
@misc{peng2026extending,
title = {{Extending the La Solubility Limit in Sr$_3$Ir$_2$O$_7$ through High-Pressure High-Temperature Synthesis}},
author = {Cheng Peng and Weiwei Xie},
howpublished = {arXiv},
year = {2026},
month = jun,
doi = {10.48550/arxiv.2606.12727},
eprint = {2606.12727},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.12727},
}
RIS
TY - UNPB
TI - Extending the La Solubility Limit in Sr_3Ir_2O_7 through High-Pressure High-Temperature Synthesis
AU - Cheng Peng
AU - Weiwei Xie
PY - 2026
DA - 2026/06/10
PB - arXiv
DO - 10.48550/arxiv.2606.12727
UR - https://arxiv.org/abs/2606.12727
AB - La-doped bilayer iridates provide an important platform for studying the evolution of the spin-orbit-assisted Mott state under electron doping, but the La solubility achieved by conventional ambient-pressure synthesis is limited. Here, we report the synthesis and physical properties of nominally La-doped (Sr_1−xLa_x)_3Ir_2O_7 (x = 0.05, 0.10, 0.15, and 0.20) prepared using high-pressure high-temperature techniques. Single-crystal X-ray diffraction refinements, supported by scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX), reveal significantly enhanced La incorporation, with nominal x = 0.05 and 0.15 corresponding to actual compositions of approximately (Sr_0.89La_0.11)_3Ir_2O_7 and (Sr_0.77La_0.23)_3Ir_2O_7, respectively. At nominal x = 0.20, the bilayer phase is no longer stabilized and instead transforms into cubic perovskite Sr_1−xLa_xIrO_3. (Sr_0.89La_0.11)_3Ir_2O_7 exhibits a ferromagnetic-like transition near 186 K accompanied by magnetic hysteresis and subtle lattice anomalies indicative of spin-lattice coupling. Despite its high electron-doping level, the compound remains strongly insulating, consistent with a heavily doped localized magnetic insulating state distinct from both parent Sr_3Ir_2O_7 and ambient-pressure La-doped samples. In contrast, (Sr_0.77La_0.23)_3Ir_2O_7 displays metal-like electronic behavior, weakened magnetic order, and enhanced carrier delocalization, although disorder-driven localization persists at low temperatures. These results demonstrate that high-pressure synthesis substantially extends the accessible doping range of bilayer iridates and reveals electronic and magnetic states inaccessible through conventional synthesis routes.
ER -