High Pressure Synthesis of All Transition Metal Oxide Perovskites and Related Materials

对具有优异性能的新型电子和磁性材料的研究激发了许多现代化学、物理和材料科学的兴趣。超导铜酸盐和磁阻锰氧化物的重大发现，加上对多铁性、燃料电池和电池混合导体以及光电子学(如W(Hite Light)LED荧光粉)的新兴趣，引起了全球对金属氧化物相关材料的兴趣。该项目的中心是钙钛矿，这是一类广泛的材料，其结构基于矿物CaTiO3的ABX3排列。钙钛矿的兴起是由其巨大的化学和结构灵活性以及优异的物理和化学性质推动的，这些性能在各自领域往往是最好的，例如用于自旋电子的铁电BaTiO3，YBa2Cu3O7高TC超导体，(La，Sr)MnO3和Sr2FeMoO6 CMR(巨磁电阻)，多铁BiFeO3，用于燃料电池的掺杂LaCrO3的混合导体，用于光伏器件的分子钙钛矿(CH3NH3)PbI3。该项目将在最近的发展基础上探索“所有过渡金属”(ATM)氧化物钙钛矿，其中TM占据了ABO3钙钛矿结构中所有的A和B位。最近几年的概念验证实验表明，这种材料可以在高压条件下合成，其中一些材料具有基于Tm阳离子有序的有用和有趣的电子性质，例如，一种从负磁阻到大正磁阻的新型开关。该项目将利用高压合成来探索一系列新的大气压和相关的富Tm氧化物钙钛矿的化学种类以及电子和磁性。压力是材料勘探中的一个重要变量。我们已经在我们的两级压力机上实现了高达22 Gpa的压力，为稳定ATM氧化物钙钛矿提供了合适的压力范围。

The search for new electronic and magnetic materials with outstanding properties motivates much of modern chemistry, physics and materials science. The major discoveries of superconducting cuprates and magnetoresistive manganites, plus renewed interests in multiferroics, mixed conductors in fuel cells and batteries, and optoelectronics such as W(hite light)LED phosphors have given rise to worldwide interest in metal oxide-related materials. This project is centred on perovskites, which are a broad class of materials with structures based on the ABX3 arrangement of the mineral CaTiO3. The inexorable rise of perovskites has been driven by their enormous chemical and structural flexibility and by their outstanding physical and chemical properties, which are often the best in their field, e.g. ferroelectric BaTiO3, YBa2Cu3O7 high-Tc superconductor, (La,Sr)MnO3 and Sr2FeMoO6 CMR (colossal magnetoresistance) for spintronics, multiferroic BiFeO3, mixed conductors such as doped LaCrO3 for fuel cells, molecular perovskites like (CH3NH3)PbI3 for photovoltaic devices. Many of these contain Transition Metals (TM) at the perovskite B-sites.This project will build on recent developments to explore 'All Transition Metal' (ATM) oxide perovskites where TM's occupy all of the A and B sites in the ABO3 perovskite structure. Proof of concept experiments in the last few years have shown that such materials can be synthesised using high pressure conditions, and some have useful and interesting electronic properties based on TM cation ordering, e.g. a novel switch from negative to large positive magnetoresistances. This project will explore the chemical variety and electronic and magnetic properties of a range of new ATM and related TM-rich oxide perovskites using high pressure synthesis. Pressure is an important variable in materials exploration. We have achieved up to 22 GPa in our two stage press providing an appropriate pressure range to stabilise the ATM oxide perovskites.