Anisotropic Sm-(Co,Fe) Nanoparticles by Surfactant-assisted Ball Milling

Authors

• Nilly Akdogan, University of Delaware, Newark, Delaware 19716, USA
• George C. Hadjipanayis, University of DelawareFollow
• David J. Sellmyer, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

2009

Comments

Published in JOURNAL OF APPLIED PHYSICS 105, 07A710 (2009). Copyright © 2009 American Institute of Physics. Used by permission.

Abstract

Magnetically hard Sm₂(Co_0.8Fe_0.2)₁₇ and SmCo₅ nanoparticles have been produced by using surfactant-assisted low- and high-energy ball milling techniques. Surfactants prevent the rewelding of the crashed particles during the milling process. Heptane was used as the milling medium and oleic acid as the surfactant. High-energy ball milling experiments took place in a milling vial with carbon steel balls by using an SPEX 8000M high-energy ball milling machine. The coercivity was found to increase with milling time with values of 2.3 kOe for Sm₂(Co_0.8Fe_0.2)₁₇ and 18.6 kOe for SmCo₅ after 4 h of milling. Transmission electron microscopy data showed that the milled powders consisted of nanoparticles with an average size of 5–6 nm and a narrow size distribution. Samples deposited on copper coated carbon grid showed self-assembled nanoparticles which could be further aligned when subjected to a magnetic field.