Magnetism of MnGa-based nanostructures

ORAL

Abstract

Materials with high magnetic anisotropy and Curie temperature well above room temperature have potential for a range of applications including high-density recording, nonvolatile memory and permanent-magnet materials. Mn$_{\mathrm{y}}$Ga (1 $\le $ y $\le $ 2) is one such compounds that can be synthesized in the tetragonal L1$_{0}$ or D0$_{22}$ structures based on the value of y in Mn$_{\mathrm{y}}$Ga. Our experimental investigation of the rapidly quenched nanostructured ribbons shows that the material with y $=$1.2, 1.4 and 1.6 prefers the L1$_{0}$ structure and that with y $=$1.9 and 2.1 prefers D0$_{22}$ structure. We have found a maximum saturation magnetization of 88 emu/g in Mn$_{1.2}$Ga which decreases monotonically to 50 emu/g as y reaches 2.1. Although both the L1$_{0}$ and D0$_{22}$Mn$_{\mathrm{y}}$Ga samples show a high Curie temperature (T$_{\mathrm{c}})$ well above room temperature, the value of T$_{\mathrm{c}}$ decreases almost linearly from 740 K for Mn$_{2.1}$Ga to 550 K for Mn$_{1.2}$Ga. We will also discuss the effect of boron doping on the structural and magnetic properties of this material.

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Authors

  • Parashu Kharel

    Nebraska Center for Materials and Nanoscience(NCMN) and Department of Physics and Astronomy, University of Nebraska, Lincoln, NE, 68588

  • Yung Huh

    NCMN and Department of Physics, South Dakota State University, Brookings, SD, 57007

  • Valloppilly Shah

    NCMN,University of Nebraska, Lincoln, NE, 68588

  • Ralph Skomski

    Department of Physics and Astronomy and NCMN, University of Nebraska, NCMN and Department of Physics and Astronomy University of Nebraska, Lincoln, NE, 68588, Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska

  • David Sellmyer

    Department of Physics and Astronomy and NCMN, University of Nebraska, NCMN and Department of Physics and Astronomy University of Nebraska, Lincoln, NE, 68588, Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska