M. Ruhle

Publications (2)3.84 Total impact

• Source

  Available from: 12.175

  Article: Enhanced magnetic coercivities in Fe nanowires

  N. Grobert, W. K. Hsu, Y. Q. Zhu, J. P. Hare, H. W. Kroto, D. R. M. Walton, M. Terrones, H. Terrones, Ph. Redlich, M. Ruhle, R. Escudero, F. Morales
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  ABSTRACT: We describe a way of generating films (≪2  mm ²; ≪40 μ m thick) of aligned Fe-filled carbon nanotubes. These Fe nanowires are usually composed of single Fe crystals, and have dimensions from 5–40 nm outer diameter and ≪10 μ m in length. The carbon tubes, which coat the wires, have external diameters of ∼20–70  nm and are ≪40 μ m in length. High-resolution electron energy loss spectroscopy, x-ray powder diffraction, and elemental mapping of the tubular structures reveal only characteristic metallic signals and the effective absence of oxygen (or any other nonmetallic element) within the wires. The material exhibits coercivities in the 430–1070 Oe range, i.e., greater than those reported for Ni and Co nanowires. © 1999 American Institute of Physics.
  Applied Physics Letters 12/1999; · 3.84 Impact Factor
• Article: Identification of electron donor states in N-doped carbon nanotubes

  R Czerw, M Terrones, JC Charlier, X Blase, B Foley, R Kamalakaran, N Grobert, H Terrones, D Tekleab, PM Ajayan, W Blau, M Ruhle, DL Carroll
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  ABSTRACT: Nitrogen-doped carbon nanotubes have been synthesized using pyrolysis and characterized by scanning tunneling spectroscopy and transmission electron microscopy. The doped nanotubes are all metallic and exhibit strong electron donor states near the Fermi level. Using tight-binding and ab initio calculations, we observe that pyridine-like N structures are responsible for the metallic behavior and the prominent features near the Fermi level. These electron rich structures are the first example of n-type nanotubes, which could pave the way to real molecular heterojunction devices.
  NANO LETTERS. 1(9):457-460.