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

Document Type

Article

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.