Microcalorimetry In Pulsed Magnetic Fields

对材料电子性质的高磁场测量已经产生了革命性的突破，这些突破改变了科学。这些进展，例如量子霍尔效应，是通过测量电输运(电阻率、霍尔效应等)来实现的。热力学探测器具有独特的能力，因为它们可以揭示其他探测器隐藏的量子态，但由于执行它们的技术困难，很少在非常高的场中进行尝试。在这里，我们建议开发一种用于测量极高脉冲磁场中的比热的新一代装置，以及一种在实验室环境中创建这种场的补充低成本装置。使用脉冲场将使量子材料热容研究的能力发生阶梯变化，因为它将极大地增加磁场空间的最大范围，从而允许研究以前无法达到的跃迁。重要的是，它还将极大地减少测量的碳足迹/成本。这一新的能力将使我们能够研究熵到前所未有的高场的演化，从而对场感应态的本质有新的见解，例如高温超导体的正常态或量子临界磁跃迁。为了让人们能够负担得起50T以上的磁场，我们还将开发一种微脉冲磁场装置。这将极大地增加进入高海拔地区的机会，提高研究人员的生产率，并意味着在国际设施中进行昂贵的实验将得到更好的准备。许多突破性的、高场的发现都是偶然的，例如高温超导体中的整数和分数量子霍尔效应和量子振荡。因此，更广泛地使用强磁场将使这种突破变得更有可能。

High magnetic field measurements of the electronic properties of materials have produced seminal breakthroughs which have transformed science. These advances, such as the quantum Hall effects were made by measuring electrical transport (resistivity, Hall effect etc). Thermodynamic probes have unique capabilities as they can reveal quantum states hidden to other probes but these are rarely attempted at very high fields because of the technical difficulties with performing them. Here we propose to develop a new generation device for measuring specific heat in very high pulsed magnetic fields, and a complementary low-cost device for creating such fields inside a laboratory environment.The use of pulsed fields would make a step-change in capability for heat-capacity studies of quantum materials, as it would greatly increase the maximum range of magnetic field-space thus allowing previously out of reach transitions to be studied. Importantly, it will also reduce enormously the carbon footprint /cost of the measurement. This new capability will allow us to study the evolution of entropy to unprecedented high fields and thus get new insights into the nature of field-induced states, such as the normal state of high temperature superconductors or quantum critical magnetic transitions. To give affordable access to magnetic fields above 50T, we will also develop a micro-pulsed magnetic field apparatus. This will enormously increase access to high fields, increasing productivity of researchers and meaning expensive experiments in international facilities will be better prepared. Many break-through, high field discoveries are serendipitous, for example integer and fractional quantum Hall effects and quantum oscillations in high temperature superconductors. So more widespread use of high magnetic field will make such breakthroughs more likely.