Collaborative Proposal: Physics of Ferromagnetic Nanorings in an External Azimuthal Field

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。当铁磁纳米环的尺寸接近单个磁畴的尺度时，它们表现出独特的磁态。闭合通量？，漩涡？状态存在于适当大小的磁盘和环中，其中圆形场线完全包含在结构中。该涡旋的手性已被提出作为一种新型存储器件的存储位，但在均匀外场下对手性的控制已被证明是具有挑战性的。这个由霍利奥克山学院和马萨诸塞大学阿默斯特分校合作的项目，通过原子力显微镜的尖端通过电流直接探索漩涡状态的切换。这种电流将产生一个控制旋涡手性的方位磁场。模拟结果表明，在涡旋之外的方向上施加磁场会产生有趣的状态，产生稳定的360度畴壁，并且将研究不对称对磁态的影响。这项工作将涉及芒特霍利奥克学院的本科生，以及博士后和研究生，促进两个机构之间的频繁互动。此外，将与K12教师和附近的斯普林菲尔德技术社区学院一起开发和纳入磁性课程材料。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。纳米级磁体表现出独特的磁态，可以用作新型数据存储设备。目前，计算机硬盘驱动器以1？和0 ?它们被编码在小条形磁铁中，北极或南极指向上方。磁性纳米环提供了一种独特的状态，没有极点，而是可以存储？和0 ?顺时针或逆时针方向的磁场被称为“漩涡”。状态。霍利奥克山学院（MHC）和马萨诸塞大学阿默斯特分校（UMass）之间的合作项目，探索磁性纳米化的物理学。马萨诸塞大学的制造设备和专业知识将用于制造纳米管。MHC的原子力显微镜能够精确地定位纳米环中心的一根细线。电流通过导线产生磁场，可以控制圆形磁化的方向，这是传统技术难以实现的壮举。这项工作将涉及芒特霍利奥克学院的本科生，以及博士后和研究生，促进两个机构之间的频繁互动。此外，将与K12教师和附近的斯普林菲尔德技术社区学院一起开发和纳入磁性课程材料。

Technical Abstract:This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Ferromagnetic nanorings exhibit unique magnetic states as the dimensions approach the scale of a single magnetic domain. The closed-flux ?vortex? state exists in appropriately sized disks and rings, in which the circular field lines are entirely contained within the structure. The chirality of this vortex has been proposed as the storage bit in a novel memory device, but control over the chirality has proven challenging with uniform external fields. This collaborative project between Mount Holyoke College and the University of Massachusetts, Amherst, directly explores the switching of the vortex state by passing a current through the tip of an atomic force microscope. This current will produce an azimuthal magnetic field that controls the vortex chirality. Simulations predict that azimuthally applied fields result in interesting states beyond the vortex, generating stable 360 degree domain walls, and effects of asymmetry on the magnetic states will be examined. This work will involve the undergraduate women at Mount Holyoke College, as well as post-docs and graduate students, fostering frequent interaction between the two institutions. Furthermore, curricular material on magnetism will be developed and included in established programs with K12 teachers and the nearby Springfield Technical Community College.Non-technical Abstract:This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Nanoscale magnets exhibit unique magnetic states that can be used as novel data storage devices. Computer hard drives presently store information in binary bits of ?1? and ?0? that are encoded in what are effectively little bar magnets with either the north or south pole pointing up. Magnetic nanorings offer a unique state that has no poles, but instead could store the ?1? and ?0? as clockwise or counterclockwise magnetic fields in what is called the ?vortex? state. This collaborative project between Mount Holyoke College (MHC) and the University of Massachusetts, Amherst (UMass), explores the physics of magnetic nanorings. The fabrication facilities and expertise at UMass will be used to make the nanorings. The atomic force microscope at MHC is capable of precisely positioning a tiny wire at the center of a nanoring. Passing a current through the wire creates a magnetic field that allows control over the direction of the circular magnetization, a feat that is difficult to accomplish with traditional techniques. This work will involve the undergraduate women at Mount Holyoke College, as well as post-docs and graduate students, fostering frequent interaction between the two institutions. Furthermore, curricular material on magnetism will be developed and included in established programs with K12 teachers and the nearby Springfield Technical Community College.