SGER: Sublithographic Patterning of Nanoscale Spintronic Devices

Ohio State University Research Foundation -Do Not Use, Columbus OH

Investigators

Abstract

SGER: Sublithographic Patterning of Nanoscale Spintronic Devices Objective: The primary technical and scientific objectives of this proposal will be the fabrication of ultra-dense arrays of ferromagnetic nanowires and their magnetic and electronic characterization, respectively. This work will provide insight into the mechanisms of nanoscale magnetism and lay the groundwork for future work ranging from the fabrication of ultra-dense magnetic memories (~ 0.5 TBit/in2) and coherent arrays of microwave oscillators to the development and exploration of nanopatterned magnetic meta-materials. Technical Merit: In recent years, control over the structure and composition of matter at nanoscopic length scales has emerged as a grand challenge facing the scientific and engineering communities. Inherent in the breadth of this challenge, however, is a remarkable opportunity to approach previously intractable problems from a new perspective. Examples include the use of biologically inspired organic templating for the low temperature, orientation specific, synthesis of both metallic and semiconducting nanocrystals and the use of molecular materials as active layers in hybrid organic-inorganic nanoscale devices and circuits. This proposal presents another such convergence, in exploiting an inherent compatibility between novel sublithographic patterning techniques and the development of spintronic devices and circuits based on the spin-transfer torque mechanism. This compatibility arises from the fact that the amplitude of the spin-transfer torque depends on spin current density, and therefore naturally lends itself to nanoscale geometries. In parallel, the development of the superlattice nanowire pattern transfer (SNAP) technique for creating massively parallel arrays of extremely dense and well indexed nanowires (1000's of wires at a pitch down to 20 nm) has allowed for the creation of crossbar circuits of up to 160,000 junctions at nearly crystallographic density. The focus of this proposal will be the implementation of this approach in Fe, Co, and Ni alloys, allowing the fabrication of magnetic nanowires at unprecedented density and laying the groundwork for magnetic tunnel junctions at sizes down to the superparamagnetic limit. These structures have potential applications including ultra-dense magnetic random access memories (MRAM), electronic and optical metamaterials, and phase coherent microwave arrays. Broader Impact: A second consequence of the breadth of the challenge inherent in nanoscale systems is that it requires a commensurate breadth of knowledge to exploit the multitude of potential solutions to a given problem. Considering this challenge from another perspective, the study of nanoscience/nanotechnology also provides an exciting opportunity to provide insight into a number of traditionally distinct disciplines, both for students training in careers in science and engineering and for the public at large. As a result, this program will incorporate an integrated plan to both prepare students for interdisciplinary research as well as lay the foundation for future outreach efforts in the community. The centerpiece of this program will be the development of an interdisciplinary course in nanoscience/nanotechnology aimed at upper level undergraduates and first year graduate students. The course will be broken into three modules, one each for physics, chemistry, and biology, and each module will provide an introduction into both why nanoscience is relevant for the appropriate discipline and the techniques and applications implicit in that particular aspect of nanotechnology. Each module will be taught by an instructor expert in the pertinent area, and the class will be advertised as broadly as possible to encourage students from diverse backgrounds to enroll. As it is clearly not practical to train each student to the level of expert in all three disciplines, the goal of this course will be rather to provide a sort of Rosetta stone for the physical sciences. More specifically, to provide students with an introduction to both the problems and solutions considered important by their colleagues so as to foster productive and successful interdisciplinary collaboration in their future careers. These activities will lay the foundation for future collaborative course development at the high school level, as well as outreach programs involving the Columbus science museum, COSI.