CAREER: Hexagonal Ferrite Thin Films for the High-Temperature Magnetoelectric Memory Effect

职业：用于高温磁电记忆效应的六方铁氧体薄膜

• 批准号: 1454618
• 负责人: Xiaoshan Xu
• 金额: $ 59.13万
• 依托单位: University of Nebraska-Lincoln
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1454618&HistoricalAwards=false
• 关键词: CAREER; Hexagonal; Ferrite; Thin; Films

NON-TECHNICAL SUMMARYThe discovery and utilization of the dynamic coupling between the electric and magnetic fields - electromagnetic waves - has revolutionized human society, particularly in the wireless communications. The "static" couplings between the electric and magnetic fields in a material (e.g. switching the north and south poles of a magnet using an electric field) are expected to have major applications in compact and energy efficient information storage and processing, sensors, and actuators. These applications are desired since the demand for information storage and processing is ever increasing while the capabilities of current technology are being exhausted. This Faculty Early Career Development (CAREER) project explores the possible static couplings between the electric and magnetic fields in new materials, such as hexagonal ferrites, by elucidating the connections between their electric, magnetic, and structural properties, and fine-tuning the materials using advanced material preparations. Integrated with the research, the educational objectives of this project are, to promote teaching undergraduate students fundamental physics by exposing them to cutting-edge research and by exploiting new student-centered pedagogical approaches, to mentor and inspire student researchers with systematic trainings for innovative research, and to engage K-12 students to stimulate their interests in science.TECHNICAL SUMMARY Switching a magnetic dipole using an electric field (magnetoelectric memory effect) - an effect that can be a working principle of the next-generation technology for information processing and storage - is unfortunately rare in known materials and restricted to low temperature. This Faculty Early Career Development (CAREER) project explores the magnetoelectric memory effect that is efficient and stable at high temperature, by the discovery of new materials or by tuning the properties of known materials experimentally. In particular, this project investigates the possible magnetoelectric memory effect in the materials that exhibit both improper ferroelectricity and improper ferromagnetism, such as hexagonal ferrites (h-RFeO3; R =Y, Ho, Lu). The specific research objectives of the proposed work are: 1) Elucidate the origin of the magnetic orderings in hexagonal ferrites. 2) Experimentally determine the magnetoelectric effect and identify the underlying mechanism in hexagonal ferrites. 3) Adjust the magnetic properties and the coupling between the magnetic and electric properties in hexagonal ferrites by tuning their structures using epitaxial thin film growth. Pulsed laser deposition method is employed to prepare single crystalline epitaxial thin film materials of tuned structures. The details of magnetic, electronic, and lattice structures are investigated using neutron scattering, x-ray spectroscopy, and x-ray diffraction respectively. The couplings between the electric and magnetic properties are studied by measuring the change of ferromagnetic properties in an electric field. Besides advancing the understanding in the magnetoelectric couplings in complex oxides in general, the success of the project may experimentally establish a new paradigm of magnetoelectric effect originated from improper ferroelectricity and improper ferromagnetism

非技术总结，电磁波和磁场之间的动态耦合发现和利用（电磁波）彻底改变了人类社会，尤其是在无线通信中。材料中电场和磁场之间的“静态”耦合（例如，使用电场切换磁铁的北极和南极）将在紧凑和节能的信息存储和处理，传感器和执行器中具有重大应用。需要这些应用程序，因为对信息存储的需求和处理的需求不断增加，而当前技术的功能正在耗尽。这个教师的早期职业发展（职业）项目通过阐明其电气，磁性和结构性能之间的连接，并使用新材料（例如六边形铁矿）中的电场和磁场之间的静态耦合，并使用材料进行微调先进的材料准备。该项目的教育目标与研究结合在一起，是为了促进教学本科生的基本物理学，通过将其暴露于尖端的研究并利用新的以学生为中心的教学方法，指导和激发学生研究人员进行创新研究的系统培训，并吸引K-12学生刺激他们对科学的兴趣。技术摘要使用电场（磁电机记忆效应）切换磁性偶极子 - 这种效果可以是下一代技术用于信息处理和存储的工作原理 - 不幸的是，在已知材料中很少见，并且仅限于低温。这个教师的早期职业发展（职业）项目探索了通过发现新材料或通过实验调整已知材料的性能在高温下在高温下高效且稳定的磁性记忆效应。特别是，该项目调查了材料中可能的磁性记忆效应，这些材料既表现出不适当的铁电性又表现出不当的铁磁性，例如六边形铁氧体（H-RFEO3; r = y，ho，ho，lu）。拟议的工作的特定研究目标是：1）阐明六角形铁氧体中磁有序的起源。 2）实验确定磁电效应并确定六边形铁氧体中的潜在机制。 3）通过使用外延薄膜的生长调整其结构，调整六角形铁氧体中磁性和电特性之间的磁性能和耦合。脉冲激光沉积法用于制备调谐结构的单晶外延薄膜材料。分别使用中子散射，X射线光谱和X射线衍射研究了磁，电子和晶格结构的细节。通过测量电场中铁磁特性的变化来研究电力和磁性之间的耦合。除了促进复杂氧化物中磁电耦合中的理解外，该项目的成功还可以在实验中建立一个新的磁电效应范式，源自不当的铁电和不当的铁电磁范围