Structural and Magnetic Characteristics of p-GaAs/MnAs Nanocluster Hybrids

ORAL

Abstract

A possible route towards semiconductor spintronic devices involves the controlled synthesis of hybrid materials that combine ferromagnetic (FM) nanoclusters within a doped semiconductor host lattice. We use molecular beam epitaxy of (Ga,Mn,Be)As followed by in situ annealing to synthesize a systematic set of samples wherein FM nanoclusters are embedded in a p-GaAs matrix. High resolution transmission electron microscopy (HRTEM) and magnetometry demonstrate our ability to reproducibly synthesize two distinct classes of materials: (a) type I samples consisting of uniformly distributed, small clusters ($\sim $6 nm); (b) type II samples consisting of a bimodal distribution of small ($\sim $6 nm) and large ($\sim $25 nm) clusters. HRTEM studies show that while the large clusters are clearly MnAs with NiAs structure, the smaller clusters are possibly zinc blende in structure but with a more complex composition. We analyze the magnetic behavior of these two classes of samples and show measurements of their transport properties. Supported by the ONR-MURI program.

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Authors

  • David Rench

    Department of Physics and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA

  • Peter Schiffer

    The Pennsylvania State University, University Park, PA, Pennsylvania State University, Department of Physics and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA, Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, PA 16802, Penn State University

  • N. Samarth

    Department of Physics and Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, Physics Dept., Penn State University, University Park PA 16802, Pennsylvania State University, Department of Physics and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA, Center for Nanoscale Science and Materials Research Institute, Penn State University, University Park PA 16802.