SQUID Magnetometer (7 Tesla)

在奥格斯堡大学的电子相关性和磁性中心，实验物理V的主席专注于研究具有新功能的强相关磁性材料。感兴趣的材料是例如skyrmion主机，受抑磁体，低维自旋系统，磁电化合物和非常规超导体。这些材料中的大多数都是在椅子上生长和仔细表征的，然后再用介电和光学光谱学以及磁共振技术等先进方法进行研究。除了X射线结构分析，SQUID测量的磁性表征是对每种新磁性材料进行可靠基础研究的必然工具。在许多情况下，对磁化强度和磁化率的研究远远超出了标准表征，例如确定磁相变的临界指数，超导体中的临界场，以及不同磁相之间相变的详细扫描。对每个磁性样品的大量强制性测量迫切需要一台新的强大的SQUID磁强计，因为现有的20多年的机器严重超载，最近需要频繁维护。我们申请SQUID磁强计，用于在最大7特斯拉的磁场中，在2 K至400 K（氦低温恒温器）和300 K至1000 K（烘箱）的温度范围内进行直流和交流磁化测量。应包括以下选项：即使对于小磁场（<0.5 mT）也能进行精确的磁场调节，用于静水压力高达13 kbar的高压池，用于电气测量的低温恒温器插入件，用于角度相关测量的旋转器。拟议的新SQUID磁强计将加速和加强目前和计划中的新多功能材料分析活动。它提供了时间的经济性（因子5-10）和扩展的参数范围（磁场、温度、压力）。这对于我们在Transregio TRR 80（“从电子相关性到功能性”）和优先计划SPP 2137（“Skyrmionics”）中成功继续开展项目至关重要，也是实现提案中描述的各种计划项目的先决条件。

At the Centre for Electronic Correlations and Magnetism of the University of Augsburg, the chair of Experimental Physics V focuses on the study of strongly correlated magnetic materials with new functionalities. Materials of interest are e.g. skyrmion hosts, frustrated magnets, low-dimensional spin systems, magnetoelectric compounds, and unconventional superconductors. Most of these materials are grown and carefully characterized in the chair, before they are studied by advanced methods like dielectric and optical spectroscopy, and magnetic resonance techniques. Besides x-ray structural analysis, the magnetic characterization by SQUID measurements is an inevitable tool for a reliable fundamental investigation of each new magnetic material. In many cases the investigations of magnetization and magnetic susceptibility go far beyond standard characterization, e.g. for determination of critical exponents at magnetic phase transitions, critical fields in superconductors, as well as the detailed scan of phase transitions between different magnetic phases. This vast number of mandatory measurements for each magnetic sample urgently demands a new powerful SQUID magnetometer, as the existing more than 20 years old machine is heavily overloaded and recently requires frequent maintenance. We apply for a SQUID magnetometer for DC- and AC-magnetization measurements in magnetic fields up to 7 Tesla maximum and in a temperature range from 2 K up to 400 K (helium cryostat) and from 300 K up to 1000 K (oven). The following options should be included: precise field regulation even for small fields (<0,5 mT), high-pressure cell for hydrostatic pressure up to 13 kbar, cryostat insert for electrical measurements, rotator for angular dependent measurements. The proposed new SQUID magnetometer will allow to accelerate and intensify the current and planned activities in the analysis of new multifunctional materials. It provides economy of time (factor 5-10) and an extended parameter regime (magnetic field, temperature, pressure). This is essential for the successful continuation of our projects within the Transregio TRR 80 (“From Electronic Correlations to Functionality”) and the Priority Program SPP 2137 (“Skyrmionics”) and it is prerequisite for the realization of various planned projects, described in the proposal.