Ferromagnetic Gd$_{100-x}$Fe$_{x}$ (x = 4 - 40) Nanostructures

ORAL

Abstract

Iron in concentrations as small as 4 at. {\%} (where the distance between Fe atoms is more than three lattice spacings) produces ferromagnetic behavior at temperatures up to 50 K above the Gd Curie temperature T$_{C}$ in Gd$_{100-x}$Fe$_{x}$ nanostructures. X-ray diffraction and XAFS show that Gd$_{100-x}$Fe$_{x}$ nanostructures made by inert-gas-condensation and melt-spinning have nanoscale hcp Gd grains with Gd-Fe grain boundaries. Magnetization and XMCD measurements indicate that, above the bulk Gd T$_{C, }$Fe atoms polarize Gd atoms and produce ferromagnetic behavior with coercivities on the order of 50-100 Oe. The coercivity decreases as the temperature decreases toward the Gd T$_{C, }$which we attribute to random anisotropy averaging produced by ordering of the hcp-Gd grains.

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Authors

  • David Schmitter

    University of Nebraska - Lincoln, University of Nebraska-Lincoln

  • Jared Goertzen

    University of Nebraska - Lincoln, University of Nebraska-Lincoln

  • Geoffrey Shelburne

    University of Nebraska - Lincoln, University of Nebraska-Lincoln

  • Tom Pekarek

    University of North Florida, Univ. of N. Florida

  • J. E. Shield

    University of Nebraska - Lincoln

  • P.M. Shand

    University of Northern Iowa, Purdue U.

  • Daniel Haskel

    Argonne National Laboratory

  • Diandra Leslie-Pelecky

    University of Nebraska - Lincoln, University of Nebraska-Lincoln