A novel ferromagnetic Kondo system MnBi-Pt

ORAL

Abstract

MnBi is one of few ferromagnetic materials possessing strong magneto-optical properties. In order to understand and control the structural, magnetic and electrical transport properties of MnBi based alloys, we have prepared Pt-alloyed MnBi thin films by sequential evaporation of Bi, Mn and Pt onto a glass substrate using an AJA e-beam evaporation system. The films have post annealed stoichiometry of Mn$_{55-x}$Pt$_{x}$Bi$_{45}$ (x = 0, 1.5, 3, 4.5). X-ray diffraction shows that Mn$_{55-x}$Pt$_{x}$Bi$_{45}$ thin films adopt a hexagonal NiAs-type structure with preferred c-axis orientation. All the films are strongly ferromagnetic at room temperature, although saturation magnetization decreases and coercivity increases with the substitution of Pt. We have observed that the electrical transport properties of MnBi are highly sensitive to external nonmagnetic impurities including Pt and show a Kondo effect at low temperatures. The origin of Kondo effect in the ferromagnetic MnBi lattice due to the substitution of a nonmagnetic impurity will be discussed.

*This work is supported by the NSF MRSEC Grant DMR - 0820521 [P. K., R. D. K.], DOE Grant DE - FG02 - 04ER46152 [R. S., D. J.S.] and NCMN.

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Authors

  • P. Kharel

    • University of Nebraska, Lincoln

  • Ralph Skomski

    • Nebraska Center for Materials and Nanoscience and Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588.
    • University of Nebraska, Lincoln
    • Department of Physics and Astronomy \& NCMN, University of Nebraska, Lincoln, NE 68588
    • Dept. Phys. \& Astr. and NCMN, University of Nebraska

  • R.D. Kirby

    • University of Nebraska, Lincoln

  • David Sellmyer

    • University of Nebraska, Lincoln
    • University of Nebraska