This project brings together researchers from New York University and IBM with the aim of furthering the understanding and application of nanometer scale magnetic devices and materials. Magnetic nanostructures are widely used in technology with the most advanced applications being found in information processing. This is a huge industry in the United States that is growing rapidly, with the ever-increasing worldwide demands for data processing and storage. It has recently been discovered that in miniature magnetic devices a direct electrical current can switch the direction of magnetization by a mechanism known as spin-transfer. This development may enable dramatic improvements in magnetic information processing and storage. There are many important and fundamental questions about the nature of the interaction between the current and magnetization that this project will address through the investigation of new device structures, materials, and unique high frequency measurement techniques available at NYU. The research will be integrated with the training of young scientists in this forefront area of magnetism research. Graduate and undergraduate students involved in this collaboration will gain by interactions between academia and industry and through the many planned exchanges between NYU and IBM. Their education will be enriched through exposure to a variety of perspectives, expertise and techniques present in an industrial setting. High school students will also participate in this research.
This NSF-GOALI award supports a project that brings together researchers in nanomagnetism from New York University and IBM with the aim of furthering the understanding of the physics of spin-transfer and applications of spin-transfer to high performance devices, such as magnetic random access memory (MRAM). Spin-transfer is a mechanism by which a spin-polarized current can alter the magnetic orientation of a nanomagnet and induce magnetic excitations such as spin-waves. Understanding the spin-transfer mechanism will likely enable dramatic improvements in magnetic information processing and storage. This is because spin-transfer offers a means to rapidly reverse the magnetization of nanomagnets with large magnetic anisotropy that would otherwise require huge local magnetic fields. The project will investigate new device structures and materials as well as use high-frequency measurements as a tool both for the characterization of material parameters and quantitative measurements of the spin-torques acting on magnetic domains and domain walls. New device structures include perpendicularly magnetized materials designed to trap domains walls, three terminal spin-valves as well as submicron-scale magnetic rings composed of soft magnetic materials. The knowledge gained may guide technological developments that will enable a reduced switching current and increased switching speed of spin-transfer MRAM. Graduate and undergraduate students involved in this collaboration will gain by interactions between academia and industry and through the many planned student exchanges between NYU and IBM. Their education will be enriched through exposure to a variety of perspectives, expertise and techniques present in an industrial setting. High school students conducting Intel Science Research will also participate in this research.
This project investigated the fundamental properties of microscopic magnets and how they respond to electrical currents, magnetic fields and temperature. Such magnets, also called nanomagnets because they are typically only composed of millions of atoms, are widely used to store information on the Internet or Web. This National Science Foundation (NSF) funded research program advanced knowledge that can enable technological advances, such as higher information storage density and faster data access times. One of the basic questions we studied is how one can magnetize such elements and the chance that they will demagnetize due to random events. Since the magnets are very small they are susceptible to be affected by their environment (such as by heat, the random motion of atoms at room temperature). We have developed theoretical models that can predict how likely it is that a magnet will demagnetize. Our models also predict how a magnet can be magnetized with an applied current using an interaction know as spin transfer torques. This is a very strong interaction associated with the fact that electrons that compose an electrical current have a magnetic moment or spin. We tested our models by conducting experiments on nanomagnetic elements using currents and magnetic fields to magnetize or demagnetize the elements and measured the time it takes for each process. In the course of these studies we have also invented devices that can improve how semiconductor chips store and retrieve digital information. The PI of this award founded a startup company--Spin Transfer Technologies--to develop the memory technology invented in this and his prior NSF awards. This project has also trained scientists in an important area of science and technology. Several of the students who were supported by his award are now leading research and development efforts in industry and in National Labs in the United States. There also been a number of undergraduates and even high school students who have participated in the research supported this award.
