NER: Atomic-Scale Magnetoresistive Sensors and Nanoscience Education

William Marsh Rice University, Houston TX

Investigators

Abstract

We propose to exploit recently developed fabrication techniques to make electronic devices with atomic-scale active regions for sensing magnetic fields. We shall examine the physics of such devices, with an eye toward optimizing them for applications under "real world" conditions (e.g. stable at room temperature in an ambient environment). The device configuration will be atomic-scale junctions between soft ferromagnetic electrodes, fabricated by electrochemical growth from lithographically defined starting electrodes. Similar junctions exhibit ballistic magnetoresistance, a large (~1000%) magnetoresistive effect with an unknown underlying detailed physical mechanism. We will examine the temperature and orientation dependence of the junction magnetoresistance in a well-controlled domain geometry to better understand the physics of these devices. This proposal is ambitious and high-risk, at the frontiers of fabrication capabilities, but with a high potential payoff magnetic sensors with an atomic-scale active region, and a detailed understanding of their underlying physics. This research program and related educational efforts will have significant impact beyond the research goals described above. Stable atomic-scale sensors with large magnetoresistive effects have the potential to be a disruptive technology for the magnetic data storage industry, much as giant magnetoresistance devices were ten years ago. Detection of local magnetic fields with sensitivity greater than existing GMR technology will enable the ongoing development of terabit/in2 storage devices. Furthermore, the PI, already active in nanoscience educational efforts, will leverage the content of this research and existing outreach programs at Rice University for lasting impact on undergraduate, graduate, and K-12 education. This NER proposal addresses the Nanoscale Devices and System Architecture theme discussed in the program announcement.