Editors : A.S. Barnard, K. Choi, D.J. Srolovitz, H. Xu
a1 pattersonm@uwstout.edu, University of Wisconsin-Stout, Dept. of Physics, Jarvis Hall 103 F Science Wing, Menomonie, WI, 54751, United States, 715 232-2153
a2 repreter@hotmail.com, University of Nebraska - Lincoln, Mechanical Engineering, Lincoln, NE, 68588-0656, United States
a3 xli2@unl.edu, University of Nebraska - Lincoln, Nebraska Center for Materials and Nanoscience, Lincoln, NE, 68588-0113, United States
a4 jshield2@unl.edu, University of Nebraska - Lincoln, Mechanical Engineering, Lincoln, NE, 68588-0656, United States
a5 dsellmyer1@unl.edu, University of Nebraska - Lincoln, Physics and Astronomy, Lincoln, NE, 68588-0113, United States
Abstract
In this study, cubic and spherical FePt clusters were created by inert gas condensation in an argon-helium dc sputter discharge under different flow and target power conditions. The plasma recipes for spherical and cubic clusters called for high He:Ar ratio, low target power and low He:Ar ratio, high target power, respectively. As expected, Langmuir probe measurements show the recipes led to larger ion density for the cubic case (2 × 108 cm−3 versus 6 × 106 cm−3 for spherical). We conclude that the larger density of argon ions increased the cluster-ion collision probability, heating the clusters in situ to promote atomic rearrangements and the formation of the ordered L10 crystal structure rather than the disordered fcc structure.
(Received November 03 2008)
(Accepted November 05 2008)
Key Words