Cryogen-free thermodynamic and transport measurement system(low T, high B)

我们申请了一种无制冷剂测量平台，用于测量低温和强磁场下的输运和热力学性质。该平台将是波鸿鲁尔大学新设立的实验物理IV(实验固态物理)教席的核心。我们将重点研究广泛的低温温度范围和强磁场中的量子材料，使用基本的热力学和输运方法-这对于理解它们的奇异性质至关重要。单晶样品是在内部准备的，这确保了系统的充分利用。样品环境：具有He-3选项的无冷媒测量平台通常提供0.4-400K的温度环境，无需提供液氦，从而使其能够连续使用-独立于商品氦的供应情况。高达14T的磁场将使高场效应的研究成为可能。测量量：本提议的中心测量量是电阻、比热容和磁化强度。与测量站“应变”(目前在椅子上处于建立阶段)一起，该平台将使研究大部分热力学和磁性量子材料的基本输运成为可能。科学问题：该测量平台将支持众多具有竞争力的项目。它将能够表征低温下的相变、磁性和基本激发。一个重要的项目(ERC)将集中在各种向列型超导体(包括Ba(Fe，Co)2As2和SrxBi2Se3)上，其中对其在极低温度和高磁场下的超导电性的表征对这一高风险/高增益项目至关重要。其他项目涉及两个有序参数共存的几个模型系统中的复合集体激发，以及反铁磁体(Sr，Ca)Co2As2在强磁场和各向异性应变下的性质。正在筹备的几个项目涉及寻找新材料，例如具有电子-结构相变耦合和磁性过渡-金属二卤化物的材料，以及计划中的卓越专题组“变形材料(科学)”中的材料研究。总而言之，主席的绝大多数项目将受益于测量平台，主要是通过对内部准备的单晶样品进行表征。该系统将通过波鸿鲁尔大学材料研究部未来的“共享实验室”倡议进一步提供给其他小组的成员。

We apply for a cryogen-free measurement platform for transport and thermodynamic properties at low temperatures and in high magnetic fields. The platform will be central for the newly set-up chair for experimental physics IV (experimental solid-state physics) at the Ruhr-University Bochum. We will focus on the investigation of quantum materials in a broad and cryogenic temperature range and in high magnetic fields using fundamental thermodynamic and transport methods – crucial for understanding their exotic properties. Single-crystalline samples are prepared in-house, which ensures the use of the system to full capacity. Sample environment: the cryogen-free measurement platform with He-3 option routinely provides a temperature environment of 0.4-400 K. No liquid Helium supply is necessary, which enables its continuous use – independent from the supply situation with the commodity Helium. Magnetic fields up to 14 T will enable the study of high field effects. Measured quantities: the central measured quantities for the present proposal are the electrical resistance, the specific heat capacity and the magnetization. Together with the measurement station „strain“ (currently in the built-up phase at the chair), the platform will enable the study of the majority of the thermodynamic quantities and the fundamental transport of magnetic quantum materials. Scientific questions: The measurement platform will enable numerous competitive projects. It will enable the characterization of phase transitions, of magnetic properties and of fundamental excitations at low temperatures. One important project (ERC) will focus on a variety of nematic superconductors (including Ba(Fe,Co)2As2 und SrxBi2Se3), where the characterization of their superconductivity at very low temperatures and in high magnetic fields is of central importance for this high-risk/high-gain project. Other projects are concerned with the composite collective excitations in several model systems for the coexistence of two order parameters, and with the properties of the antiferromagnet (Sr,Ca)Co2As2 in high magnetic fields and under anisotropic strain. Several projects in preparation concern the search for new materials, e.g., materials with coupled electronic-structural phase transitions and magnetic transition-metal dichalcogenides, as well as the materials research in the planned excellence cluster “Transforming Materials (Science)”. Altogether, the vast majority of the projects at the chair will profit from the measurement platform, mostly via the characterization of the single-crystal samples prepared in-house. The system will further be made available to members of other groups via a future “shared-labs” initiative of the materials research department of the Ruhr-University Bochum.