NSF-Europe: Collaborative Study of Geometrically Frustrated Magnetic Material: New Materials and New Physics

NSF-欧洲：几何受挫磁性材料的合作研究：新材料和新物理学

• 批准号: 0353610
• 负责人: Peter Schiffer
• 金额: $ 45.81万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-06-01 至 2008-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0353610&HistoricalAwards=false
• 关键词: NSF; Europe; Collaborative; Study; Geometrically

This is an international collaborative research project that was submitted in response to NSF Solicitation NSF 02-135. The project will investigate the unusual properties of geometrically frustrated magnets, materials in which the interactions between atomic spins compete with each other due to the triangular geometry of the magnetic sublattice. This leads to highly degenerate ground states where the interaction energies cannot all be simultaneously minimized. This in turn prevents ordinary magnetic ordering down to temperatures well below the energy scale of the spin-spin interaction. The low temperature magnetic properties will be investigated via a collaborative approach involving two U.S. investigators, who specialize in materials chemistry and magnetothermodynamic measurements, and two European groups: One in the areas of nuclear magnetic resonance (NMR) and other measurements at Laboratoire de Physique des Solides, Universite Paris-Sud, the other in the areas of neutron diffraction and theory at University College London. One research theme is the chemical synthysis of new geometrically frustrated magnets with the specific goals of investigating new frustrating lattice types and of finding materials that are both highly frustrated and that can be grown as high-quality single crystal samples. The second theme is the study of effects of chemical substitution on geometrically frustrated systems. Students involved in the research will participate in international research activities, together with traditional and cutting edge training that will prepare them for careers in academe, industry or government.%%%This is an international collaborative research project that was submitted in response to NSF Solicitation NSF 02-135. The project will investigate the unusual properties of a class of materials known as geometrically frustrated magnets. In contrast to ordinary magnets, and due to the geometrical arrangement of magnetic atoms in the lattice, these materials cannot attain a unique, low temperature, lowest-energy arrangement for their magnetic moments. The key geometry leading to the effect has magnetic atoms placed at the vertices of triangles. These systems are fundamentally different from other magnetic materials in that their properties at low temperatures cannot be understood within current theoretical models. Understanding geometrical frustration in magnets has implications for complex systems as diverse as superconducting junction arrays or neural networks, and may also provide insight into computational algorithms. The research is a collaboration between four groups, two in the U. S., one in the United Kingdom and one in France. The two U.S. investigators have a long record of working with a diverse group of students and involving graduate students and undergraduates in every stage of the research process. Students involved in the research will participate in international research activities, together with traditional and cutting edge training that will prepare them for careers in academe, industry or government.

这是一个国际合作研究项目，是针对NSF招标NSF 02-135提交的。该项目将研究几何沮丧的磁铁的异常特性，其中由于磁性sublattice的三角形几何形状，原子旋转之间的相互作用相互竞争。这导致了高度退化的基础状态，即不能同时最小化相互作用能量。反过来，这防止了普通的磁排序降低到远低于自旋旋转相互作用的能量尺度的温度。低温磁性特性将通过一种涉及两名美国研究人员的协作方法进行研究，他们专门研究材料化学和磁化性动力学测量，两个欧洲群体：一个在核磁共振共鸣（NMR）的领域（NMR），以及在Physique de Physique de Physique des solidides，Paris-paris-sud的Laboratoire de Physique dessite sud中的其他测量中，是在大学中的其他领域。一个研究主题是对新几何沮丧的磁铁的化学合成，其特定目标是研究新的令人沮丧的晶格类型，并找到既高度沮丧又可以作为高质量的单晶样品而种植的材料。 第二个主题是化学替代对几何挫败系统的影响的研究。参与研究的学生将参加国际研究活动，以及传统和最先进的培训，这将使他们为学术界，行业或政府的职业做好准备。%%％这是一个国际协作研究项目，该项目是针对NSF招标NSF 02-135提交的。该项目将研究一类称为几何挫败磁铁的材料的异常特性。与普通磁铁相比，由于晶格中磁原子的几何排列，这些材料无法获得独特的，低温，最低的能量排列，以使其磁矩。导致效果的关键几何形状具有磁原子位于三角形的顶点。这些系统从根本上与其他磁性材料有所不同，因为在当前的理论模型中无法理解其在低温下的性质。了解磁体中的几何挫败感对像超导连接阵列或神经网络一样多样化的复杂系统具有影响，并且还可能提供对计算算法的见识。这项研究是四个群体之间的合作，其中两组在美国，一个在英国，一个在法国。两位美国调查人员在研究过程的每个阶段都与各种学生一起工作，并参与研究生和本科生。参与研究的学生将参加国际研究活动，以及传统和最先进的培训，这将为学术界，工业或政府的职业做好准备。