受限低维量子磁性材料的强磁场ESR研究

项目名称： 受限低维量子磁性材料的强磁场ESR研究

项目编号： No.11474110

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 欧阳钟文

作者单位： 华中科技大学

项目金额： 85万元

中文摘要： 低维量子磁性是凝聚态物理研究的热点。本项目针对当前研究的不足和蕴涵的研究机遇，尝试在块体低维量子磁性材料中引入新的自由度- - -纳米受限，并利用脉冲强磁场ESR研究其异常基态。首先制备系列不同晶粒尺寸的纳米晶样品，表征其形貌和晶体结构；然后通过变温和变频ESR测量，研究纳米晶样品的磁有序、磁激发和自旋隙等，建立它们与强磁场和纳米晶粒尺寸之间的关联，并通过分析拓扑结构、各向异性和磁交换相互作用，揭示其微观起源。重点研究S=1/2小自旋Cu、V氧化物和自旋阻挫的材料体系，特别关注已接近量子临界点的材料，探索在这些材料中引入自旋隙或长程有序，并发现新的量子效应和量子相变的可能性。

中文关键词： 强磁场ESR；纳米受限；低维量子磁性；自旋隙；量子相变

英文摘要： Low-dimensional quantum magnetism is an important topic of condensed matter physics. With the deficiencies and opportunities in present studies, we will try to introduce new degree of freedom-nanoscale in the bulk low-dimensional quantum magnetic materials and perform pulsed high-field ESR study on the novel ground state of these materials. First, nano-grain samples with various sizes will be synthesized and their morphology and crystal structure will be characterized. Second, by means of temperature- and frequency-dependent ESR measurements, we will study the magnetic ordering, magnetic excitation and spin gap of nano-grain samples. The relationship between the ground-state properties and magnetic field as well as nano-grain size will be constructed. The mechanism will be understood by analyzing the topological structure, magnetic anisotropy and exchange interaction. Much attention will be paid on the S=1/2 Cu and V oxides and the low-dimensional frustrated systems. In particular, we will focus on those materials which have been close to quantum critical point. It is expected to introduce spin gap or long-range magnetic order in these materials and find new quantum phenomena and transitions.

英文关键词： High-field ESR;Nanoscale confinement;Low-D quantum magnetism;Spin gap;Quantum phase transition