Magnetism of Quantum Spins Systems in Low Dimensions

这项研究涉及研究过渡金属络合物的磁性，其中的金属自旋被限制在一维或二维空间(一维、二维)。由于低维耦合，材料呈现出有趣的磁相图，它是温度、磁场和压力的函数。相行为将通过一系列实验技术进行研究，其中包括磁化率和比热测量，温度低至50毫克尔文，场强高达9特斯拉。这些热力学研究是对光学和磁共振光谱研究的补充。在S=2的线性链状材料中，绘制了第一临界磁场的温度依赖关系图，并与理论和模拟研究进行了比较，预测了可能出现的新的临界行为。在两个维度上，将研究基于普鲁士蓝类似物的新型层状材料。这些新系统的磁光开关温度低于150K，参与该项目的学生将学习广泛的现代实验技术，其中许多需要获得与获得超低温和非常高的磁场相关的技能。这项培训为企业、学术界和政府部门的职业生涯提供了极好的准备。这项研究的主要影响是基础物理，尽管层状磁性材料的研究可能与信息存储行业有一些技术上的相关性。本项目重点研究限制在一到两个空间维度的新型磁性系统。低维系统的一个引人注目的方面是，它们的性质往往是定性和定量可预测的，因为由于对快速计算机的访问增加，现在可以使用新的分析和数值工具。实验研究需要在低温和强磁场的极端情况下进行研究。这项工作对这些模型进行了严格的测试，并得出了与信息存储行业相关的见解。参与的学生接受各种跨学科领域的培训，即物理、化学和材料科学，并为进入技术多样化的工作大军做好准备。

This research involves the study of the magnetic properties of transition metal complexes in which the metal spins confined to one or two spatial dimensions (1D, 2D). Because of the low-dimensional couplings, the materials exhibit interesting magnetic phase diagrams as a function of temperature, magnetic field, and pressure. The phase behavior will be investigated by a range of experimental techniques, which include susceptibility and specific heat measurements that extend to temperatures as low as 50 millikelvin and field strengths up to 9 Tesla. These thermodynamic studies complement optical and magnetic resonance spectroscopy investigations. In one linear-chain material with S=2, the temperature dependence of the first critical magnetic field will be mapped and compared with theory and simulation studies, which predict possible new critical behavior. In two dimensions, novel layered materials based upon Prussian blue analogues will be investigated. These new systems are magneto-optically switched below 150 K. Students participating in the project will learn a wide range of modern experimental techniques, many of which require skills associated with attaining ultra low temperatures and very high magnetic fields. This training provides excellent preparation for careers in industry, academe and government. The primary impact of the research is on fundamental physics, though the research dealing with layered magnetic materials may have some technological relevance to the information storage industry.This project focuses on the investigation of novel magnetic systems confined to one or two spatial dimensions. A striking aspect of low dimensional systems is that their properties are often qualitatively and quantitatively predictable since new analytical and numerical tools are now available due to increased access to fast computers. The experimental research requires investigations at the extremes of low temperatures and high magnetic fields. The work presents stringent tests of the models and yields insight relevant to the information storage industry. The participating students receive training in a variety of interdisciplinary fields, namely physics, chemistry, and materials science, and are well prepared to enter the technologically diverse work force.