Magnetic Studies on Nd$_{2}$Fe$_{14-x}$Mn$_{x}$B Nanoflakes and Nanoparticles Produced by Surfactant-Assisted High Energy Ball Milling

ORAL

Abstract

High temperature magnetic ordering studies on rare earth transition-metal nanoparticles and nanoflakes present a great challenge due to the very high reactivity of these materials. It is well known that Mn substitution for Fe in Nd$_{2}$Fe$_{14}$B compound decreases the Curie temperature to a temperature range that allows for reliable measurements to be made. In this work, we have studied the magnetic properties of Mn substituted Nd$_{2}$Fe$_{14}$B particles in the temperature range of 50-400 K. Nd$_{2}$Fe$_{14-x}$Mn$_{x}$B nanoparticles and nanoflakes have been produced by surfactant-assisted high-energy ball milling (SA-HEBM). Different size nanoparticles have been obtained by varying the milling conditions. Anisotropic Nd$_{2}$Fe$_{14-x}$Mn$_{x}$B nanoparticles have been found with a size from 13 to 25 nm. Both the nanoparticles and nano-flakes showed high coercivities at low temperatures, with values at 50 K of 2.4 kOe and 5.5 kOe, respectively. The Curie temperature was determined from the temperature dependence of magnetization. We have observed a different magnetic ordering behavior in the nanoparticles with Curie temperatures that are higher when compared to the bulk values.

*Work supported by NSF DMR-1005871.

–

Authors

  • George Hadjipanayis

    • Department of Physics and Astronomy, University of Delaware, Newark, DE, U.S.A.
    • Department of Physics and Astronomy, University of DE, Newark, DE, 19711, USA
    • Department of Physics and Astronomy, University of DE, Newark, DE, 19716, USA
    • University of Delaware

  • Nilay Gunduz Akdogan

    • Department of Physics and Astronomy, University of Delaware, Newark, DE, U.S.A.

  • Wanfeng Li

    • Department of Physics and Astronomy, University of Delaware, Newark, DE, U.S.A.