Cryogen-free dilution refrigerator with 3D vector magnet for transport studies of quantum materials

我们的目标是通过购买配备(9，1，1)T矢量磁铁的稀释式制冷机来发展LMU在量子材料方面的研究工作。这套完整的设备将填补LMU的一个关键空白，因为缺乏这样的系统阻碍了对量子材料的竞争性研究。事实上，稀释冰箱允许将任何感兴趣的材料冷却到8mK以下，稳定性低于5mK。这个温度足够低，足以抑制热波动，从而让源自电子关联的量子效应显现出来。一旦处于这种强烈简并的基态，三维矢量磁铁就可以完全控制自旋极化。这使得深入研究现代凝聚态物理学的一个主要难题：磁激发及其与超导等其他量子电子相的相互作用/竞争。我们的目标是通过两种互补的技术-低频(DC)和高频(RF)电子传输-来探索这些相关现象，这要归功于一系列高过滤的48 DC和8 RF传输线。传输线的高质量过滤对于抑制低温下电子的电磁加热和保存量子现象学至关重要。为了完成我们的测量设置，包括前置放大器和锁定放大器，我们希望获得一个高清晰度示波器和一个网络分析仪。最后，我们希望购买一种无制冷剂系统，既要简单使用，因为设备将在LMU之间共享，又要考虑到液氦价格的不断上涨而长期经济。

We aim to develop the LMU‘s research endeavours on quantum materials by the acquisition of a dilution refrigerator equipped with a (9,1,1)T vector magnet. This complete apparatus will fill a critical void at the LMU where the absence of such a system hinders competitive research on quantum materials. Indeed, a dilution refrigerator permits to cool any material of interest down to 8mK with a stabiblity below 5mK. This temperature is low enough to suppress thermal fluctuations and thus to let quantum effects, stemming from electronic correlations, manifest themselves. Once in this strongly degenerate ground state, the three-dimensional vector magnet grants a complete control of the spin polarization. This allows to study in-depth a major conundrum of modern condensed matter physics: magnetic excitations and their interplay/competition with other quantum electronic phases such as superconductivity. We aim to probe these correlated phenomena by two complementary techniques, low-frequency (DC) and high-frequency (RF) electronic transport, thanks to an array of highly-filtered 48 DC and 8 RF transmission lines. High-quality filtering of the transmission lines is paramount to suppress electromagnetic heating of the electrons at low temperatures and preserve the quantum phenomenology. To complete our measurement setup, composed of pre-amplifiers and lock-in amplifiers, we wish to acquire acquire a high-definition oscilloscope and a network analyzer. Finally, we wish to buy a cryogen-free system for both simplicity of usage, as the equipement will be shared among the LMU, and long-term economy in light of the ever increasing price of liquid helium.