Perpendicular-Current Spin-Polarized Transport Studies

该计划涉及两个相关的项目，在计算机行业的潜在应用。 密歇根州立大学（MSU）的一组研究人员将研究和操纵交替的铁磁和非铁磁金属层的磁性。 在第一个项目中，将对精心选择的金属对之间的界面的电阻率进行精确测量，电阻率等于样品面积与其电阻的乘积。将这些结果与计算结果进行比较，将检验我们目前对磁性多层膜中电子输运的理解，从而为未来的技术设计提供基础。 第二个项目涉及金属磁性多层膜中的电流诱导磁化翻转。 这项研究是非常感兴趣的写磁随机存取存储器和作为一个潜在的新一代读头的不必要的噪声的可能来源。 为了测试预测，MSU小组将测量开关电流和磁阻如何随着磁性和非磁性金属层的许多不同组合而变化，这些组合使用其多功能纳米制造设施制备。通过参与该项目，研究生和本科生将获得规划和开展尖端科学研究的经验。该计划还涉及与法国和荷兰的科学家合作。直到最近，人们还认为，在计算机中存储信息所需的磁性层中的磁化反转可以通过施加外部磁场来实现。 密歇根州立大学的一组研究人员帮助证明，在垂直于多层膜的方向上通过足够大的电流可以诱导磁化转换。 为了实现这一点，多层的横向尺寸需要小于1微米，这需要现代的“纳米纤维”技术。拟议的研究将研究磁性和非磁性金属多层膜的不同组合，以了解电流诱导磁化切换的物理基础。研究小组将对精心挑选的金属对之间界面的电磁特性进行精确测量。这些测量与计算的比较将检验我们对磁性多层膜中电子输运的基本理解，从而为技术设计提供基础。 这些项目可能会导致新的设备用于计算机硬盘。 通过参与该项目，研究生和本科生将获得规划和开展与技术进步直接相关的尖端科学研究的经验。 该计划还涉及与其他国家的科学家合作。

This program involves two related projects with potential applications in the computer industry. A team of researchers at the Michigan State University (MSU) will investigate and manipulate the magnetic properties of alternating ferromagnetic and nonmagnetic metal layers. In the first project, precision measurements of the specific resistance, a quantity equal to the product of the sample area and its electrical resistance, of interfaces between carefully chosen pairs of metals will be made. Comparison of these results with calculations will test our current understanding of the electronic transport in magnetic multilayers, thereby providing the basis for future technological designs. The second project deals with current-induced magnetization switching in metallic magnetic multilayers. This study is of great interest both for writing magnetic random access memory and as a possible source of unwanted noise in potential new generation read-heads. To test predictions, the MSU group will measure how both the switching current and the magnetoresistance vary with many different combinations of magnetic and non-magnetic metal layers, prepared using their versatile nano-fabrication facilities. By participating in this project, graduate and undergraduate students will gain experience in planning and carrying out cutting-edge scientific research. The program also involves collaborations with scientists in France and Holland. Until recently, it was assumed that reversal of magnetization in magnetic layers, needed for information storage in computers, could be effected by applying an external magnetic field. A team of researchers at the Michigan State University has helped to show that passing a large enough current in the direction perpendicular to the multilayer can induce magnetization switching. In order to achieve this, the lateral dimensions of the multilayer need to be less than one micrometer, which requires modern "nanofabrication" techniques. The proposed research will study different combinations of magnetic and non-magnetic metal multilayers to understand the physics underlying current-induced magnetization switching. The research team will make precision measurements of the electrical and magnetic properties of the interfaces between carefully chosen pairs of metals. Comparison of these measurements with calculations will test our fundamental understanding of electronic transport in magnetic multilayers, thereby providing the basis for technological design. These projects could lead to new devices for use in computer hard disks. By participating in this project, graduate and undergraduate students will gain experience in planning and carrying out cutting-edge scientific research that directly relates to technological progress. The program also involves collaborations with scientists in other countries.