Phys. Rev. Lett. 81, 2799–2802 (1998)Enhanced Magnetoresistance in Insulating Granular Systems: Evidence for Higher-Order TunnelingReceived 12 May 1998; published in the issue dated 28 September 1998 We study the temperature and bias-voltage dependence of the magnetoresistance (MR) in insulating Co-Al-O granular films. The MR exhibits strong temperature dependence and is enhanced more than 20% at low temperatures, while it has no appreciable change in the bias-voltage dependence. The results provide clear evidence for the successive onset of higher-order processes of spin-dependent tunneling between large granules through intervening small ones with strong Coulomb blockade. The remarkable contrast between the temperature and bias-voltage dependence of the MR is consistently explained. © 1998 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevLett.81.2799
DOI:
10.1103/PhysRevLett.81.2799
PACS:
75.70.Pa, 73.40.Gk, 75.50.Cc, 81.05.Rm
|
|
About | Terms and Conditions | Subscriptions | Search | Help
Use of the American Physical Society websites and journals implies that the user has read and agrees to our Terms and Conditions and any applicable Subscription Agreement. Physical Review®, Physical Review Letters®, Reviews of Modern Physics®, and Physical Review Special Topics® are trademarks of the American Physical Society.