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

所有已知的磁性材料的晶体都具有磁性，无论在晶体的方向上进行测量。此外，当晶体加热到一定温度（称为居里温度）以上时，磁性就会消失。这个EAGER项目旨在建立一种令人兴奋的全新磁性材料的存在，这种材料在给定的晶体方向上是磁性的，而在其他方向上是非磁性的。尽管自19世纪末和20世纪现代磁学理论发展之初，人们就开始猜测这些物质的存在，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，使用纳米制造的设备来测量如此少量的热交换，同时测量样品的电学特性。虽然这是一个高风险的项目，但从中获得的积极结果将具有变革性，并在激发发现类似材料的努力和扩大当前对磁性物理的理论认识方面产生高回报。由于居里温度是一种基本的材料属性，所有依赖于它的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执行器。该项目将为一名博士后提供工作机会，并指导两名本科生进行与微细加工、磁学、量热学和电学性质有关的实验，这些实验与学术界和工业界具有广泛的相关性。这个EAGER项目试图建立一种具有各向异性居里温度的全新磁性材料的存在。这种材料在特定的温度下具有独特的性质，沿着给定的晶体方向具有铁磁性，而沿着其他方向具有顺磁性。虽然它们的存在长期以来一直被推测和理论化，但该项目确定了表现这种不寻常的磁性行为所需的关键材料特征。一组新颖的实验是专门设计的，以证明在一种材料中，其磁化率对晶体取向有明显的依赖性。这个高风险项目的成功结果将是变革性的，从基础和技术的角度来看都将产生高回报，刺激实验努力发现类似的材料，并使现有的磁性物理理论框架得以扩展。由于材料的居里温度是一种固有属性，所有依赖于它的效应也会表现出不寻常的定向行为，从而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提供攻读终身教职的机会，并指导两名本科生，从事与微加工、磁学、pJ量热和电子输运相关的实验，这些实验与学术界和工业界有广泛的相关性。

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.