Batch synthesis of rare-earth nickelates electronic phase transition perovskites via rare-earth processing intermediates

Abstract

The rare-earth nickelates (RENiO₃) exhibit an exceptional complex electronic phase diagram and multiple electronic phase transitions that enrich promising applications in correlated electronic devices beyond conventional semiconductors. Nevertheless, the practical applications of RENiO₃ are challenged by their intrinsic thermodynamic metastability in material synthesis and high material cost. Therefore, developing an economical strategy to achieve the batch synthesis of RENiO₃ is of vital importance. In this work, we enlarged the synthesis amount of RENiO₃ up to 20 g per batch using chloride (KCl) assisted molten salt reaction. By optimizing the reaction conditions, the powder of RENiO₃ with the cubic shape and average size of ~ 2 μm was effectively synthesized, while their phase purity exceeded 95%. In addition, the cost to synthesize RENiO₃ was further reduced by using rare-earth extraction intermediate products as the raw materials, instead of using the pure rare-earth precursors. It also achieved wide adjustments in the metal-to-insulator-transition temperature from 160 to 420 K without significantly reducing the transition sharpness. By enlarging the synthesis amount and the reducing the cost, it paves the way to the device application of RENiO₃.

Graphical abstract

摘要

稀土镍基氧化物 (RENiO₃) 表现出异常复杂的电子相图和多重电子相变, 这些超越传统半导体的性能提高了其在相关电子器件应用中的可能性。然而, 材料自身固有的热力学亚稳态和高昂的材料成本给RENiO₃的器件应用增加了难度, 因此, 开发一种经济的策略来实现RENiO₃的批量合成至关重要。在这项工作中, 我们使用氯化物 (KCl) 作为助熔剂, 通过优化反应条件, 有效地合成了晶粒为立方形状、平均粒径约2 μm的稀土镍基氧化物粉末, 其相纯度超过95%。此外, 以稀土富集物取代高纯单一稀土氧化物作为原料, 可以进一步降低材料合成的成本。我们在RENiO₃中实现了金属-绝缘体转变 (MIT) 温度从160到420 K的大范围调整, 其转变尖锐度没有显著降低。通过有效地提高其合成量并降低其成本, 本工作有助于进一步推动RENiO₃在相关电子器件制造中的应用。