Rosalin M, Irshad K A, Joseph Boby, Telang Prachi, Singh Surjeet, S Muthu D V, Sood A K
Department of Physics, Indian Institute of Science, Bangalore 560012, India.
Elettra-Sincrotrone Trieste S.C. p.A., S.S. 14, Km 163.5 in Area Science Park, Basovizza 34149, Italy.
J Phys Condens Matter. 2024 Aug 9;36(45). doi: 10.1088/1361-648X/ad69ed.
The pyrochlore iridates,IrO, show a wide variety of structural, electronic, and magnetic properties controlled by the interplay of different exchange interactions, which can be tuned by external pressure. In this work, we report pressure-induced iso-structural phase transitions at ambient temperature using synchrotron-based x-ray diffraction (up to ∼20 GPa) and Raman-scattering measurements (up to ∼25 GPa) of the pyrochlore series (Sm_{1-x}Bi)IrO(= 0, 0.02, and 0.10). Our Raman and x-ray data suggest an iso-structural transition in SmIrOatPc∼ 11.2 GPa, associated with the rearrangement of IrOoctahedra in the pyrochlore lattice. The transition pressure decreases to ∼10.2 and 9 GPa for= 0.02 and 0.10, respectively. For all the samples, the linewidth of three phonons associated with Ir-O-Ir (A1gand) and Ir-O (T2g4) vibrations show anomalous decrease up toPc, due to decrease in electron-phonon interaction.
烧绿石铱酸盐（IrO）展现出由不同交换相互作用的相互作用所控制的多种结构、电子和磁性特性，这些特性可通过外部压力进行调节。在这项工作中，我们利用基于同步加速器的X射线衍射（高达约20吉帕）和拉曼散射测量（高达约25吉帕），报道了烧绿石系列（Sm_{1-x}Bi）IrO（x = 0、0.02和0.10）在室温下压力诱导的同结构相变。我们的拉曼和X射线数据表明，SmIrO在Pc约为11.2吉帕时发生同结构转变，这与烧绿石晶格中IrO八面体的重排有关。对于x = 0.02和0.10的情况，转变压力分别降至约10.2吉帕和9吉帕。对于所有样品，与Ir - O - Ir（A1g和）以及Ir - O（T2g4）振动相关的三个声子的线宽在达到Pc之前呈现反常减小，这是由于电子 - 声子相互作用的减小。
