Spectroscopic and Local Magnetic Measurements in High-Spin Molecular Nanomagnets

高自旋分子纳米磁体的光谱和局部磁测量

• 批准号: 0451605
• 负责人: Myriam Sarachik
• 金额: $ 48万
• 依托单位: CUNY City College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-15 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0451605&HistoricalAwards=false
• 关键词: Spectroscopic; Local; Magnetic; Measurements; Spin

Molecular magnets contain a large number of (nearly) identical magnetic clusters of total spin on the order of 10. Borderline between classical and quantum magnetism, these nanomagnets hold promise for high-density information storage and, possibly, quantum computation. The goal of the present project is to gain a deeper understanding of Mn-12, a prototypical member of the class. (1) High resolution spectroscopic measurements will be performed using synchrotron radiation over a very broad range of frequencies; the aim is to investigate the internal degrees of freedom of the magnetic clusters and to study the line-widths and line shapes which will yield information regarding disorder, internal magnetic fields and electron-phonon coupling strengths; magnetic avalanches will be studied to determine whether they are accompanied by coherent super-radiant emission, as has been recently suggested; (2) Micro-Hall bar detectors will be used to investigate the local spatial and temporal evolution of spin reversal inside the material as the magnetization relaxes toward equilibrium under controlled conditions and during magnetic avalanches. Participation in forefront research in the laboratory provides high-level education and training for both graduate and undergraduate students. It should be noted that City College draws its undergraduate student population from every economic stratum and from diverse ethnic and racial backgrounds. %%% Molecular nanomagnets, sometimes referred to as "single molecule magnets" are potential candidates for high-density information storage and quantum computation. Quantum computation is a new and entirely different computing paradigm based on quantum phenomena. Rather than having two possible "classical" values, 0 or 1, the quantum mechanical elements of quantum computers, called "qubits", represent a far broader set of possibilities, enabling much greater computing power. The goal of the current proposal is to gain a deeper understanding of a prototypical member of this class of materials, Mn12-acetate, which consists of a very large number of identical clusters of 12 manganese atoms that form magnetic molecules regularly arranged in an organic crystal; each molecule is a little magnet that is equivalent to 20 times the magnetism of a single electron. Spectroscopic studies will be performed at low temperatures at the synchrotron light source at Brookhaven, and measurements will be taken at City College of New York of the local magnetization at low temperatures on a length scale of microns using very small Hall bars. Participation in forefront research in the laboratory provides high-level education and training for both graduate and undergraduate students. It should be noted that City College draws its undergraduate student population from every economic stratum and from very diverse ethnic and racial backgrounds

分子磁体包含大量（几乎）相同的总自旋为10数量级的磁团。这些纳米磁铁介于经典磁性和量子磁性之间，有望用于高密度信息存储，甚至可能用于量子计算。本项目的目标是更深入地了解该类的典型成员Mn-12。(1)高分辨率光谱测量将在非常宽的频率范围内使用同步辐射进行；目的是研究磁性团簇的内部自由度，并研究线宽和线形状，这将产生有关无序，内部磁场和电子-声子耦合强度的信息；将对磁雪崩进行研究，以确定它们是否像最近提出的那样伴随着相干超辐射发射；(2)在可控条件下和磁雪崩过程中，利用微霍尔棒探测器研究材料内部自旋反转的局部时空演化。参与实验室的前沿研究为研究生和本科生提供了高水平的教育和培训。应该指出的是，城市学院吸引了来自各个经济阶层和不同民族和种族背景的本科生。分子纳米磁体，有时被称为“单分子磁体”，是高密度信息存储和量子计算的潜在候选者。量子计算是基于量子现象的一种全新的、完全不同的计算范式。量子计算机的量子力学元素（称为“量子位”）不是只有两个可能的“经典”值，即0或1，而是代表了更广泛的可能性，从而实现了更强大的计算能力。当前提案的目标是更深入地了解这类材料的原型成员mn12 -醋酸盐，它由大量相同的12个锰原子簇组成，形成有规则地排列在有机晶体中的磁性分子；每个分子都是一个小磁铁，其磁性相当于单个电子的20倍。光谱研究将在布鲁克海文的同步加速器光源下在低温下进行，并将在纽约城市学院使用非常小的霍尔棒测量低温下微米长度尺度的局部磁化。参与实验室的前沿研究为研究生和本科生提供了高水平的教育和培训。应该指出的是，城市学院的本科学生来自各个经济阶层，来自不同的民族和种族背景