Collaborative: EAGER: Demonstration that Thin Film Phase Transformations Can Be Monitored at High-Temperature and High-Pressure in a Diamond Anvil Cell

协作：EAGER：证明可以在金刚石砧池中的高温高压下监测薄膜相变

• 批准号: 2031331
• 负责人: Jason Nicholas
• 金额: $ 6.5万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-01-15 至 2023-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2031331&HistoricalAwards=false
• 关键词: Collaborative; EAGER; Demonstration; Thin; Film

Phase transitions and the associated volume changes strongly influence materials’ properties. When occurring in minerals in subduction zones - where one tectonic plate dives underneath another - they may cause earthquakes. Preliminary observations suggest that phase boundaries (where transitions occurred) are influenced by changes in mineral grain size and stress state. However, such effects are still poorly understood because of experimental limitations. Indeed, it is challenging to tune minerals’ grain size and stress state at the extreme pressures and temperatures prevailing in subduction zones. Here, the researchers explore the capabilities of a new experimental approach which allows such tuning. They produce thin films of mineral with controlled grain size and stress state using state-of-the-art deposition techniques. They then probe the mineral stability at the extreme conditions of the deep Earth using high-pressure devices. This work fosters technological transfers between Materials Science and Mineral Physics. Its outcomes have broad implications, notably regarding the stability of thin films for incorporation into everyday devices. The project also provides support for a graduate student trained in a multidisciplinary environment.Here, silica (SiO2) thin films with variable crystallite sizes and biaxial stress states are fabricated via Pulsed Laser Deposition by modulating the growth conditions and choice of substrate. These thin films are then placed within the independently modulated hydrostatic stress field of a diamond anvil cell. This high-pressure device can produce very high pressures at the tips of two opposing diamonds. The films’ properties are probed in situ with visible light and/or x-rays at various pressures and temperatures. The goal is to map out how given SiO2 crystallite size and/or biaxial stress state changes the pressure and temperature conditions of silica phase boundaries. More generally, the team explores whether Pulsed Laser Deposition can produce geologically relevant thin films with tunable stress states, crystallite sizes and orientations. Such a novel tool could be transformative for the study of phase transformations - as well as other processes related to transport properties and chemical reactions - occurring in the deep Earth.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

相变和相关的体积变化强烈影响材料的性能。当它们出现在俯冲带（一个构造板块潜入另一个构造板块之下）的矿物中时，可能会引起地震。初步观察表明，相界（发生相变的地方）受到矿物粒度和应力状态变化的影响。然而，由于实验的限制，这种效应仍然知之甚少。事实上，在俯冲带的极端压力和温度下，调整矿物的粒度和应力状态是一项挑战。在这里，研究人员探索了一种允许这种调谐的新实验方法的能力。他们使用最先进的沉积技术生产具有控制晶粒尺寸和应力状态的矿物薄膜。然后，他们使用高压设备探测地球深处极端条件下的矿物稳定性。这项工作促进了材料科学和矿物物理学之间的技术转移。其结果具有广泛的意义，特别是关于薄膜的稳定性纳入日常设备。该项目还为在多学科环境中训练的研究生提供支持。本文通过调节生长条件和衬底的选择，采用脉冲激光沉积技术制备了具有可变晶粒尺寸和双轴应力状态的二氧化硅（SiO2）薄膜。然后将这些薄膜置于金刚石砧细胞的独立调制的静水应力场中。这种高压装置可以在两个相对的钻石的尖端产生非常高的压力。在不同的压力和温度下，用可见光和/或x射线原位探测薄膜的性质。目标是绘制出给定SiO2晶粒尺寸和/或双轴应力状态如何改变二氧化硅相边界的压力和温度条件。更一般地说，该团队探索脉冲激光沉积是否可以生产具有可调应力状态、晶体尺寸和取向的地质相关薄膜。这样一种新颖的工具对于研究发生在地球深处的相变——以及与传输性质和化学反应相关的其他过程——具有革命性意义。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。