Early stages of direct L1₀ FePt nanocluster formation: The effects of plasma characteristics

Authors

M. M. Patterson, University of Nebraska - Lincoln
A. Cochran, University of Nebraska - Lincoln
J. Ferina, University of Nebraska - Lincoln
X. Rui, University of Nebraska - Lincoln
T. A. Zimmerman, University of Nebraska - Lincoln
Zhiguang Sun, University of Nebraska - LincolnFollow
Matthew J. Kramer, Ames Laboratory, USDOE,Follow
David J. Sellmyer, University of Nebraska-LincolnFollow
Jeffrey E. Shield, University of Nebraska - LincolnFollow

Document Type

Article

Date of this Version

3-2010

Comments

Published in J. Vac. Sci. Technol. B 28(2), Mar/Apr 2010. Copyright © 2010 American Vacuum Society. Used by permission.

Abstract

The formation of FePt nanoclusters via gas condensation has attracted a great deal of attention. The clusters normally form with the magnetically soft A1 structure rather than the desired L1₀ structure with high magnetocrystalline anisotropy. This work has examined the effects of plasma characteristics on the early stages of order in the formation L1₀ FePt nanoclusters via inert gas condensation. The plasma characteristics have been modified to control ion density in the nanocluster condensation region. Increased ion density results in more cluster-ion collisions. The energy imparted to the clusters as a result of these collisions allows atomic rearrangements to form the ordered structure. The results indicate that controlled ion density directly impacts the early stages of FePt nanocluster ordering, according to high-resolution electron microscopy structure observations and coercivity measurements.