Magnetic and Magnetoelectric Interactions at Interfaces in Ideal Antiferromagnetic Systems

技术摘要：该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。磁性纳米结构的基础研究导致了具有新功能的设备，这是由于利用电子自旋传输信息的能力的发展，从而制造出新的电子设备（自旋电子学）。近年来，人们对利用同时具有磁性和铁电性的多铁性材料来进一步控制具有电场的自旋电子器件产生了浓厚的兴趣。大多数本构多铁性材料是具有弱磁-铁电耦合的氧化物绝缘体，因此有必要研究替代的多铁性体系。本文将对BaMF4 （M =过渡金属）多铁薄膜进行研究。由于在保持其晶体结构不变的情况下修改这些材料的磁性结构相对容易，因此将识别和优化薄膜内部和界面处的磁-铁电耦合的性质。除了标准磁强计和铁电测量外，中子散射将用于确定这些反铁磁性和多铁性材料的磁性结构。这些材料的隧道结也将被研究，试图对它们的磁和磁电激励进行光谱测量。该项目将通过参与西弗吉尼亚大学的教育和推广项目，为保持美国在科学和技术领域的竞争力做出贡献，这些项目旨在吸引和留住本科生和研究生阶段未被充分代表的少数民族学生。其中包括为本科生和研究生提供的夏季研究项目，以及为优秀的少数民族研究生提供为期一年的奖学金。本奖项由2009年美国复苏与再投资法案（公法111-5）资助。磁性纳米结构是最近几项技术创新的基础，这些创新导致了更小、更高效的数据存储和电子设备。最近，人们对开发称为多铁性的新材料很感兴趣，这种材料不仅具有强磁响应，而且还能响应电压的变化，这将使制造具有多种功能的电子设备成为可能；也就是说，对电子和磁信号都有反应的设备。该项目将包括基于氟化物而不是通常的氧化物制造多铁纳米结构，并研究其磁性和电子特性。通过优化这些材料对外加电压的磁响应，将开发出比现有设备更快、更节能的电子和数据存储设备。该项目将通过参与西弗吉尼亚大学的教育和推广项目，为保持美国在科学和技术领域的竞争力做出贡献，这些项目旨在吸引和留住本科生和研究生阶段未被充分代表的少数民族学生。其中包括为本科生和研究生提供的夏季研究项目，以及为优秀的少数民族研究生提供为期一年的奖学金。

TECHNICAL ABSTRACTThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Fundamental research in magnetic nanostructures has led to devices with new functionality due to the development of the ability to use the spin of the electron to transmit information and thus make novel electronic devices (spintronics). In recent years there has been much interest in using multiferroic materials, which are simultaneously magnetic and ferroelectric, to further control spintronic devices with electric fields. Most intrinsic multiferroic materials are oxide insulators with a weak magnetic-ferroelectric coupling, and therefore there is a need to study alternative multiferroic systems. Here, BaMF4 (M = transition metal) multiferroic thin films will be studied. Because it is relatively easy to modify the magnetic structure of these materials while keeping their crystalline structure unchanged, the nature of the magnetic-ferroelectric coupling within the bulk of the film and at the interfaces will be discerned and optimized. In addition to standard magnetometry and ferroelectric measurements, neutron scattering will be used to determine the magnetic structure of these antiferromagnetic and multiferroic materials. Tunnel junctions of these materials will also be studied in an attempt to perform spectroscopic measurements of their magnetic and magnetoelectric excitations. This project will contribute to the effort of maintaining American competititveness in science and technology fields by participating in educational and outreach programs at West Virginia University geared towards attracting and retaining underrepresented minority students at the undergraduate and graduate levels. These include summer research programs for both undergraduate and graduate students as well as recruiting outstanding minority graduate students for year-long fellowships.NON-TECHNICAL ABSTRACTThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Magnetic nanostructures have been the basis of several recent technological innovations that have led to small, more efficient data storage and electronic devices. Recently, there has been much interest developing new materials, called multiferroics, that not only have a strong magnetic response, but also respond to a change in voltage, which would enable the fabrication of electronic devices with multiple functionalities; that is, devices that respond to both electronic and magnetic signals. This project will consist of fabricating multiferroic nanostructures, based on fluoride compounds rather than the usual oxides, and studying their magnetic and electronic properties. By optimizing the magnetic response of these materials to applied voltages, electronic and data storage devices that are faster and more power efficient than current devices will be developed. This project will contribute to the effort of maintaining American competititveness in science and technology fields by participating in educational and outreach programs at West Virginia University geared towards attracting and retaining underrepresented minority students at the undergraduate and graduate levels. These include summer research programs for both undergraduate and graduate students as well as recruiting outstanding minority graduate students for year-long fellowships.