Anomalous Transport Properties in Acceptor-Type Magnetic GICs

  • N-C. Yeh
  • K. Sugihara
  • J. T. Nicholls
  • G. Dresselhaus
Part of the NATO ASI Series book series (NSSB, volume 148)

Abstract

Magnetic phase transitions have been studied in both donor and acceptor-type magnetic GICs using AC magnetic susceptibility χ and magnetization M measurements.1 However, C6Eu is the only GIC for which a magnetic phase diagram has been successfully determined using magnetoresistance (transport) measurements.2 The strong coupling between graphite layers and Eu layers in C6Eu results in strong scattering effects on the graphite conduction π-electrons by the magnetic excitations of the Eu ions. Therefore dramatic changes in the magnetoresistance of C6Eu are observed as the system undergoes magnetic phase transitions. In contrast, acceptor-type magnetic GICs have a much weaker magnetic coupling between intercalate and graphite layers because of the relatively larger spacing between the graphite and the magnetic species.3,4,5,6 Therefore the change in magnetoresistance due to changes in magnetic ordering is expected to be smaller than for the case of C6Eu. In this work we show that transport-property measurements (magnetoresistance and temperature-dependent zero-field resistivity) can yield measurable effects associated with magnetic phase transitions for the acceptor-type magnetic stage-1 and stage-2 CoC12-GICs. Thus studies on the transport properties of acceptor magnetic GICs provide a complementary way to investigate the magnetic phase diagrams.1 In addition, such measurements provide information on the π-d electron coupling constants (J πd) and the interplane exchange coupling constants (J′).7

Keywords

Magnetic Phase Magnetic Phase Transition Graphite Layer Magnetic Phase Diagram Negative Magnetoresistance 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

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    N.-C. Yeh, K. Sugihara, J. T. Nicholls, G. Dresselhaus and M. S. Dresselhaus, unpublished.Google Scholar
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    L. Hulthen, Arkiv. Mat. Astron. Fysik, 26A, No. 11 (1938).Google Scholar

Copyright information

© Springer Science+Business Media New York 1986

Authors and Affiliations

  • N-C. Yeh
    • 1
  • K. Sugihara
    • 1
  • J. T. Nicholls
    • 1
  • G. Dresselhaus
    • 1
  1. 1.Massachusetts Institute of TechnologyCambridgeUSA

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