EAGER: A Novel Class of Magnetic Materials with Anisotropic Curie Temperature

EAGER：一种具有各向异性居里温度的新型磁性材料

• 批准号: 0964830
• 负责人: Harsh Chopra
• 金额: $ 18.08万
• 依托单位: SUNY at Buffalo
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2014-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0964830&HistoricalAwards=false
• 关键词: EAGER; Novel; Class; Magnetic; Materials

NON-TECHNICALAll known crystals of magnetic materials possess magnetism regardless of the crystal direction in which measurements are made. Moreover, the magnetic properties disappear when the crystal is heated above a certain temperature, called the Curie temperature. This EAGER project seeks to establish the existence of an exciting and entirely new class of magnetic materials that are magnetic in a given crystal direction while being non-magnetic along other directions. While the existence of such materials has been conjectured ever since the beginnings of the development of the modern theory of magnetism in the late 19th and the 20th centuries, the proof of their existence has remained elusive. Experimental proof requires unconventional and ultra-sensitive instrumentation, employing a nanofabricated device to measure such small quantities of heat exchange simultaneously with electrical properties of the sample. While a high-risk project, positive results obtained from it would be transformative and yield high payoff in spurring efforts to discover similar materials and expanding current theoretical understanding of the physics of magnetism. Since the Curie temperature is a fundamental material property, all effects dependent on it would also exhibit unusual behavior, potentially leading to a gamut of new magnetic sensors and actuators. The project would provide opportunities for a post-doctoral fellow to work, and mentor two undergraduate students, on experiments related to microfabrication, magnetism, calorimetry, and electrical properties, which have broad relevance to academia and industry. TECHNICALThis EAGER project seeks to establish the existence of an entirely new class of magnetic materials that have anisotropic Curie temperature. Such materials would have the unique property, at a specific temperature, of being ferrimagnetic along a given crystal direction while being paramagnetic along other directions. While their existence has long been conjectured and theorized, the project identifies key materials characteristics necessary for the manifestation of such unusual magnetic behavior. A novel set of experiments was specifically designed to demonstrate the effect in a material that exhibits a distinct dependence of its magnetic susceptibility on crystal orientation. The successful outcome of this high-risk project would be transformative and yield a high payoff from both fundamental as well as technological viewpoints, spurring experimental efforts to discover similar materials as well as enabling the expansion of the current theoretical framework of the physics of magnetism. Since the Curie temperature of a material is an intrinsic property, all effects dependent on it would also exhibit unusual directional behavior, leading to a gamut of new magnetic sensors and actuators. The project will provide opportunities for a post-doctoral fellow to pursue a tenure track faculty position and to mentor two undergraduate students, working on experiments related to microfabrication, magnetism, pJ calorimetry, and electron transport, which have broad relevance for academia and industry.

非磁性所有已知的磁性材料的晶体都具有磁性，而不管进行测量的晶体方向如何。此外，当晶体被加热到一定温度以上时，磁性消失，称为居里温度。这个EAGER项目旨在建立一个令人兴奋的和全新的磁性材料类别的存在，在给定的晶体方向是磁性的，而沿沿着其他方向是非磁性的。虽然自19世纪末和20世纪现代磁学理论开始发展以来，这种材料的存在就已经被证实，但它们存在的证据仍然难以捉摸。实验证明需要非常规和超灵敏的仪器，采用纳米制造的设备来测量这种少量的热交换，同时测量样品的电特性。虽然这是一个高风险的项目，但从中获得的积极成果将是变革性的，并在促进发现类似材料和扩大目前对磁性物理学的理论理解方面产生很高的回报。由于居里温度是一种基本的材料特性，因此依赖于它的所有效应也会表现出不寻常的行为，这可能会导致一系列新的磁传感器和致动器。 该项目将为一名博士后研究员提供工作机会，并指导两名本科生进行与微加工，磁性，量热和电气特性相关的实验，这些实验与学术界和工业界具有广泛的相关性。EAGER项目旨在建立一种全新的具有各向异性居里温度的磁性材料。这种材料在特定温度下具有独特的性质，即沿给定晶体方向沿着是亚铁磁性的，而沿其它方向是顺磁性的沿着。虽然它们的存在早已被证实和理论化，但该项目确定了这种不寻常的磁性行为表现所必需的关键材料特性。一组新的实验是专门设计来证明在一种材料中的效果，这种材料表现出其磁化率对晶体取向的明显依赖。这个高风险项目的成功结果将是变革性的，并从基础和技术角度产生高回报，刺激实验努力发现类似的材料，并使磁性物理学的当前理论框架得以扩展。由于材料的居里温度是一种固有特性，因此依赖于它的所有效应也会表现出不寻常的方向行为，从而产生一系列新的磁传感器和执行器。该项目将为博士后研究员提供机会，以追求终身教职，并指导两名本科生，从事与微细加工，磁性，pJ量热法和电子传输相关的实验，这些实验对学术界和工业界具有广泛的相关性。