MRS Proceedings

Table of Contents - Volume  577  - Symposium H – Advanced Hard and Soft Magnetic Materials  

Editors : M. Coey, L.H. Lewis, B-M. Ma, T. Schrefl, L. Schultz, J. Fidler, V.G. Harris, R. Hasegawa, A. Inoue, M.E. McHenry


Hard Magnetic Nanoparticles and Nanocomposites

1999 MRS Spring Meeting.

Anit Giria1, Krishna Chowdarya1 and Sara A. Majeticha1 c1

a1 Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213


Many high performance permanent magnets are nanostructured materials. The magnetic properties of nanoparticles are discussed in terms of characteristic length scales, including the maximum monodomain size and the exchange length. Experimental results for ball milled SmCo5 nanoparticles are presented, showing deviations from idealized behavior. Because of the short exchange length, this can be understood in terms of independent nucleation of reverse domains in grains within larger particles. With a much longer exchange length, FeCo alloy nanoparticles show reduced coercivity in a high density compact, in accordance with the random anisotropy model. The SmCo5 and FeCo nanoparticles were mixed and compacted in an attempt to make an exchange spring nanocomposite. However, significant exchange between the hard and soft phases was not observed because the sample density was too low. Processing considerations for improved co-compaction of these nanoparticles are discussed.


c1 Author to whom correspondence should be addressed. email: