Abstract Iridates of the pyrochlore A2Ir2O7 family are interesting materials whose low-temperature properties depend sensitively on the A/Ir ratio. Due to specific difficulties, namely: (i) the volatile nature of IrO2 above 1323 K, and (ii) slow reaction kinetics between IrO2 and A2O3 below 1323 K (where A is a members of the lanthanide series), it is challenging to prepare phase pure and stoichiometric A2Ir2O7 samples using the conventional solid state reaction (SSR) method in a reasonably short time. To overcome these limitations, we synthesized A2Ir2O7 with A = Sm, Gd, Dy, and Er using a wet chemical reaction (WCR) method in a single sintering step at T = 1273 K (a temperature well below the sublimation point of IrO2) for 12 h, and compared their electrical resistivity, magnetic susceptibility and specific heat with the SSR samples. We show that WCR samples exhibit metal-to-insulator & all-in all-out transitions in agreement with previous reports. The high density, low-sintering temperature, lack of IrO2 losses, and shorter preparation time are some of the attractive features of WCR method. This should be useful in exploring the true ground state properties of these materials in future.

中文翻译：

---

烧绿石铱酸盐A2Ir2O7的一次性湿法化学合成及物理性质，（A = Sm、Gd、Dy和Er）

摘要 烧绿石 A2Ir2O7 族的铱化物是一种有趣的材料，其低温特性敏感地取决于 A/Ir 比。由于特定的困难，即：（i）IrO2 在 1323 K 以上的挥发性，以及（ii）IrO2 和 A2O3 之间在 1323 K 以下的缓慢反应动力学（其中 A 是镧系元素的成员），制备具有挑战性使用传统的固态反应 (SSR) 方法在相当短的时间内获得纯相和化学计量的 A2Ir2O7 样品。为了克服这些限制，我们在 T = 1273 K（远低于 IrO2 的升华点的温度）下使用湿化学反应 (WCR) 方法在单个烧结步骤中合成了 A = Sm、Gd、Dy 和 Er 的 A2Ir2O7，用于12 h，并将其电阻率、磁化率和比热与 SSR 样品进行比较。我们表明 WCR 样品表现出金属到绝缘体和全进全出的转变，与之前的报告一致。高密度、低烧结温度、没有 IrO2 损失和更短的制备时间是 WCR 方法的一些吸引人的特征。这对于将来探索这些材料的真实基态特性应该很有用。