Room Temperature Single Phase Magnetoelectric Ceramics Based on Cation Engineered Hexaferrite Structures

非技术描述：实现具有强大磁电效应的单相材料将使各种实用和先进的磁电子器件能够用于：无线通信、雷达和传感；大型数据分组的存储、处理和传输；以及为有望影响广泛商业和电子系统与平台的新一代多功能电子产品构建框架。该项目可能带来商业回报，预计将扰乱现有的全球电子市场，确保美国公司早日进入市场份额并创造大量就业机会。该项目的成功实施将显著和积极地影响社会的科技界(S和科技界)，并应对与增加科学、技术、工程和数学(STEM)学科中人数偏低的少数群体有关的重大社会经济挑战。该项目的教育和外联目标旨在处理建立和实施STEM价值管道的机会。这些目标有两个方面：i)确定、招收、留住和教育高中/中学、本科生和研究生，使他们掌握磁性、材料和技术的基础和应用方面的知识；ii)增加科学和工程专业，特别是磁性材料和技术界中代表性不足的少数群体的人数。该项目具体的更广泛的影响活动包括为波士顿罗克斯伯里预备特许学校的5年级、6年级、7年级和8年级的中学生建立夏季科学磁性夏令营：这是一所少数民族人口占绝大多数(近100%)的中学。该项目解决了STEM价值管道中经常被忽视的一个方面，即识别、招募和教育高中生从事科学和工程职业。技术细节：迄今为止报告的所有单相磁电材料在低温和/或非常高的磁场下都能发挥作用，严重限制了它们的应用。这项研究具有实现实用材料的潜力，这些材料可以在室温下操作，并具有最小的磁场偏置。具体地说，螺旋Y型六元铁氧体系统，包括Ba2-xSrxZn2Fe12O22和Ba2Zn2-xMgxFe12O22，已经被证明具有磁电性能，即使在低温(~5K)或高H场(~10Koe)下也是如此。在之前由美国国家科学基金会资助的研究中，这些PI已经证明了通过使用交替靶激光烧蚀沉积技术在铁氧体材料的晶胞亚晶格中重新分配阳离子的能力。结果表明，微波和磁性能有了显著的提高，如增加了饱和磁化强度、磁各向异性和Néel温度。从头算电子结构研究用于指导实验研究，并确定用于定制特定性质的首选位置。这种定向阳离子工程的方法在提高铁电有序温度和降低六角铁氧体的外场需求方面有很大的希望。结合深入的阳离子分布研究，这项研究将为有效建立磁电效应及其潜在应用的基础知识库提供新的见解。该项目更广泛的影响活动包括为波士顿罗克斯伯里预备特许学校的5年级、6年级、7年级和8年级中学生建立夏季科学磁性夏令营。此外，研究生将参与这个项目的所有方面，包括第一原理密度泛函理论、最先进的薄膜加工以及先进的同步辐射工具的应用，以预测和确认阳离子单元细胞分布，同时向他们介绍世界领先的国家实验室的第一手经验。

NON-TECHNICAL DESCRIPTION: The realization of single phase materials exhibiting a strong magnetoelectric effect will enable a wide variety of practical and advanced magnetoelectronic devices used in: wireless communication, radar, and sensing; storage, manipulation, and transmission of large data packets; and in building the framework for a new generation of multifunctional electronics that promises to impact a broad range of commercial and electronic systems and platforms. The project could lead to commercial payoffs, anticipated to be disruptive to existing global electronic markets ensuring U.S. companies early entry market share and significant job creation. The successful implementation of the project will significantly and positively impact society's science and technology (S&T) communities, as well as address important socio-economic challenges related to increasing the number of underrepresented minorities in science, technology, engineering and mathematics (STEM) disciplines. The project's education and outreach goals are designed to address opportunities in establishing and implementing the STEM value pipeline. These goals are two-fold: i) to identify, recruit, retain, and educate students at the high school/middle school, undergraduate, and graduate levels in the fundamentals and applied aspects of magnetism, materials and technologies, and ii) to increase the number of underrepresented minorities in the science and engineering professions, and in particular, in the magnetic materials and technology communities. The project's specific broader impact activities include the establishing of the Summer Science Magnetism Camp for rising 5th, 6th, 7th, and 8th grade middle school students of the Roxbury Preparatory Charter School of Boston: A middle school having an overwhelming minority population (nearly 100%). This project addresses one aspect of the STEM value pipeline often overlooked, that is, the identification, recruitment and education of pre-high school students for careers in science and engineering.TECHNICAL DETAILS: All single phase magnetoelectric materials reported to date function at cryogenic temperatures and/or very high magnetic fields severely limiting their utility. This research holds the potential of realizing practical materials that could be operated at room temperature and with minimal magnetic bias fields. Specifically, helical Y-type hexaferrite systems, including Ba2-xSrxZn2Fe12O22 and Ba2Zn2-xMgxFe12O22, have been shown to possess magnetoelectric properties, albeit at low temperatures (~5 K) or under high H-fields (~10 kOe). In prior NSF-funded research, these PIs have demonstrated the ability to re-distribute cations among unit cell sublattices in ferrite materials by employing the alternating target laser ablation deposition technique. As a result, substantial enhancement of microwave and magnetic properties, such as increased saturation magnetization, magnetic anisotropy and Néel temperature, has been demonstrated. Ab-initio electronic structure studies where used to guide the experimental research and to identify preferred sites for tailoring specific properties. This methodology, of targeted cation engineering, holds great promise for increasing the ferroelectric ordering temperature and reducing applied field requirements in hexaferrites. Combined with in-depth cation distribution studies, this research will yield new insights in effectively building the fundamental knowledge base of the magnetoelectric effect and it's potential applications. The project's broader impact activities include the establishment of the Summer Science Magnetism Camp for rising 5th, 6th, 7th, and 8th grade middle school students of the Roxbury Preparatory Charter School of Boston. Additionally, graduate students will participate in all aspects of this project that will include first principles density functional theory, state-of-the-art thin film processing, and the application of advanced synchrotron radiation tools to predict and confirm cation unit cell distribution while introducing them to first hand experience at world leading national laboratories.