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

点击翻译按钮获取中文摘要

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.