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.

当相变和相关的体积变化发生在俯冲带（一个板块潜入另一个板块下方）的矿物中时，它们可能会引起地震，相界（发生相变的地方）会受到相变的影响。然而，由于实验的限制，人们对这种影响仍然知之甚少。事实上，研究人员在俯冲带普遍存在的极端压力和温度下调整矿物的晶粒尺寸和应力状态是具有挑战性的。这他们利用最先进的沉积技术来生产具有受控晶粒尺寸和应力状态的矿物薄膜，然后利用地球深处的极端条件来探测矿物的稳定性。这项工作促进了材料科学和矿物物理学之间的技术转移，对于薄膜融入日常设备的稳定性具有广泛的影响。该项目还为在多学科环境中接受培训的研究生提供支持。这里，二氧化硅通过调节生长条件和选择基材，通过脉冲激光沉积制造具有可变微晶尺寸和双轴应力状态的 (SiO2) 薄膜，然后将这些薄膜放置在金刚石砧室的独立调节的静水应力场中。 -压力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特性。 SiO2 微晶尺寸和/或双轴应力状态改变了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产生具有可调应力状态、微晶尺寸和方向的地质相关薄膜。可能对地球深处发生的相变以及与传输特性和化学反应相关的其他过程的研究具有变革性。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准。