Transition from negative magnetoresistance behavior to positive behavior in Co₂₀ (Cu_1-xGe_x)₈₀ ribbons

Authors

J. He, Shenyang National Laboratory for Materials Science and International Centre for Materials Physics, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, People's Republic of China
Z.D. Zhang, Shenyang National Laboratory for Materials Science and International Centre for Materials Physics, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, People's Republic of China
J. Ping Liu, University of Nebraska-LincolnFollow
David J. Sellmyer, University of Nebraska-LincolnFollow

Date of this Version

3-11-2002

Comments

Published by American Institute of Physics. Appl. Phys. Lett. 80, 1779-1781 (2002). ©2002 American Institute of Physics. Permission to use. http://apl.aip.org/jap/.

Abstract

We report a transition of the giant magnetoresistance (GMR) behavior in nanocrystalline Co₂₀ (Cu_1-xGe_x)₈₀ ribbons from negative to positive, as the semiconductor Ge substitutes for the Cu matrix. The growth of the hexagonal Co₃Ge₂ compound leads to a change of the physical origin of the GMR. The normal spin-dependent transport behavior in the CoCu granular system evolves into Coulomb blockade behavior of electronic tunneling in ribbons with a Co/Co₃Ge₂/Co junctionlike configuration.