Cryogen-free dilution refrigerator system with selected options

具有选定选项的无制冷剂稀释制冷系统

• 批准号: 448942660
• 金额: --
• 依托单位: Julius-Maximilians-Universität Würzburg
• 依托单位国家: 德国
• 项目类别: Major Research Instrumentation
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 无数据
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/448942660?language=en
• 关键词: Cryogen; free; dilution; refrigerator; system

We propose to purchase a cryogen-free dilution refrigerator appropriate for the incorporation of a SQUID magnetometer, for the purpose of studying magnetization properties at millikelvin temperatures. While Squid operating down to about 1.5K are omnipresent, systems working at lower temperatures are absent in the field. There are however significant questions, with regards to magnetic and superconducting properties of Topological insulators which require precisely such an instrument to address. For example, consider the electrical quantum effects that form the basis of the new SI unit system. A promising new material class for applications in this field are the magnetic topological insulators, which allows the quantum Hall resistors to be realized without a magnetic field, in the form of the quantum anomalous Hall effect (QAHE). However, the nature of the ferromagnetic state in these topological insulators is still unclear. To understand this state, it must be measured under the same conditions where the samples exhibit the QAHE, which at present is well below 1K. A major objective is thus to develop techniques to accurately characterize the magnetic and structural properties of the QAHE devices, especially V-doped (Bi,Sb)Te system with high resolution using the SQUID sensor that can work in variable temperatures from 30K down to 10mK, which will allow us to answer some fundamental physics questions on the nature of the ferromagnetic state in this material. In addition to this primary aim, the availability of mK-SQUID will be beneficial to projects on topological superconductivity and to our other investigation on magnetic TIs in general. This instrument will provide a unique functionality in this field, and will allow us to significantly move forward the understanding of these important novel materials.

我们建议购买适合掺入鱿鱼磁力计的无低温稀释冰箱，以研究Millikelvin温度下的磁化特性。虽然乌贼无处不在，但在野外缺乏在较低温度下工作的系统。但是，关于拓扑绝缘子的磁性和超导特性，存在重大问题，这些拓扑绝缘子需要精确解决此类仪器。例如，考虑构成新SI单元系统基础的电量子效应。磁性拓扑绝缘子是在该领域应用的有希望的新材料类别，它允许在没有磁场的情况下以量子异常霍尔效应（qahe）的形式实现量子霍尔电阻器。但是，这些拓扑绝缘子中铁磁状态的性质尚不清楚。要了解该状态，必须在样品显示QAHE的相同条件下进行测量，QAHE目前远低于1K。因此，一个主要的目标是开发技术以准确表征QAHE设备的磁性和结构性特性，尤其是使用squid传感器高分辨率的V型（BI，SB）TE系统，该系统使用squid传感器可以在30k的可变温度下工作，从30k下降到10MK，这将使我们能够回答有关Ferromagnity eytemagnity Meality of fereromagnecte in ofer Ferromagnecty of fereromagnecte of fereromagnecte in naters of fereromagnecten M材中的一些基本问题。除了这一主要目标外，MK-squid的可用性将对拓扑超导性项目以及我们对磁TI的其他研究有益。该仪器将在该领域提供独特的功能，并使我们能够显着发展对这些重要新颖材料的理解。