Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9834206 | Journal of Magnetism and Magnetic Materials | 2005 | 4 Pages |
Abstract
We present results for magnetotransport measurements on multiwall-carbon nanotubes (MWCNT) contacted by cobalt electrodes. By measuring the V(I) characteristics at constant magnetic fields and different orientation of the magnetization directions in the Co electrodes, we were able to determine both current and voltage dependences of the magnetoresistance (MR) effects. These tunneling MR values are compared with the directly measured MR at constant current with sweeping magnetic field. The V(I) curves show an ohmic behavior at 295Â K and a non-linear tunneling behavior at 4.2Â K. With decreasing bias current the MR increased up to 60% at 4.2Â K, and with decreasing bias voltages even up to 175%. The MR disappears at high bias current (voltages) and temperatures higher than 40Â K. For most of the samples the current dependences of the MR were found to be nearly symmetric upon reversing the current direction. However, in some cases we also observed a sign change of the MR as function of the applied current, which suggests an inversion of the spin polarization in one of the Co interfaces.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
H. Vinzelberg, B. Zhao, I. Mönch, J. Schumann, C.M. Schneider,