Cluster-assembled exchange-spring nanocomposite permanent magnets

Authors

X. Rui, University of Nebraska - Lincoln
Zhiguang Sun, University of Nebraska - LincolnFollow
Yinfan Xu, University of Nebraska - LincolnFollow
David J. Sellmyer, University of Nebraska-LincolnFollow
Jeffrey E. Shield, University of Nebraska - LincolnFollow

Document Type

Article

Date of this Version

5-15-2005

Comments

Published by American Institute of Physics. J. Applied Physics 97, 10K310 (2005). ©2005 American Institute of Physics. Permission to use. http://jap.aip.org/jap/.

Abstract

Isotropic nanocomposite magnetic structures were produced via cluster assembly routes with energy products reaching 18 MG Oe. Gas aggregation produces Fe clusters with an average size less than 10 nm with a very narrow size distribution, and these were embedded in a hard magnetic matrix by cosputtering of FePt. Structures produced were crystallographically isotropic with Fe cluster phase content ranging from 0 to 30 vol %. The coercivity decreased from 13 kOe as Fe cluster content increased. Single-phase-type hysteresis loops indicating excellent exchange coupling at low Fe cluster content give way to a stepped demagnetization loop at an Fe cluster content greater than 20%. The energy product initially increased with Fe cluster content, then decreased.