Principle of Operation: Hard phase stiffens response of soft high-magnetization phase in magnetic nanocomposite structures.

Metallic magnetism is a time-honored field of study that in recent years has undergone a renaissance, thanks in part to Office of Science support. Research at Argonne National Laboratory on thin-film metallic multilayers is widely recognized as providing the basis for the discovery by others of giant magnetoresistance (GMR), an effect used widely today in recording heads in magnetic data storage devices. Related research has resulted in new GMR materials and structures, as well as contributions to the development and understanding of colossal magnetoresistance, a more powerful effect that may be used in future recording devices. Research at Brookhaven National Laboratory and Idaho National Engineering and Environmental Laboratory on hard magnets (permanently magnetized materials) explained the link between microstructure and properties in magnets made of rare earth materials; magnetic properties were improved dramatically through the design of microstructures on the nanoscale. Other work focuses on understanding and exploiting mixtures of hard and soft magnets with high magnetic strength. (The magnetization in soft magnets can be changed with applied magnetic fields.)

Scientific Impact: These studies have advanced the science of magnetic materials and paved the way for manufacture of magnet structures with greater mechanical strength and stability. Researchers benefit from these materials through their use in permanent magnet devices at Office of Science-supported synchrotrons and most other light sources around the world.

Social Impact: Magnetic materials are used in many industrial and consumer devices such as motors, generators, and computers. Improvements in magnet properties and processing characteristics will enhance energy efficiency; for example, the use of rare earth magnets in more efficient electric motors could save the nation several billion dollars annually.

Reference: L. H. Lewis, A. R. Moodenbaugh, D. O. Welch and V. Panchanathan, "Stress, Strain and Technical Magnetic Properties in "Exchange-Spring" Nd2Fe14B + a-Fe Nanocomposite Magnets", J. Phys. D.: Appl. Phys. 34 (2001) 744-751.

D. J. Branagan, M. J. Kramer, Yali Tang, R. W. McCallum, D. C. Crew and L. H. Lewis, "Engineering Magnetic Nanocomposite Microstructures", J. Materials Science, 35(14): 3459-3466, July 2000.

E. E. Fullerton, C. H. Sowers, J. E. Pearson, X. Z. Wu, D. Lederman, and S. D. Bader, "A General Approach to the Epitaxial Growth of Rare-Earth-Transition-Metal Films," Appl. Phys. Lett. 69, 2438 (1996).

E. E. Fullerton, M. J. Conover, J. E. Mattson, C. H. Sowers, and S. D. Bader, "Oscillatory interlayer coupling and giant magnetoresistance in epitaxial Fe/Cr(211) and (100) superlattices", Phys. Rev. B 48, 15755 (1993).

URL: http://www.msd.anl.gov/groups/mf/decades.htm

Technical Contact: Don Freeburn, Office of Basic Energy Sciences, 301-903-3156

Press Contact: Jeff Sherwood, DOE Office of Public Affairs, 202-586-5806

SC-Funding Office: Office of Basic Energy Sciences