Phys. Rev. Lett. 89, 206804 (2002) [4 pages]Dephasing by Extremely Dilute Magnetic Impurities Revealed by Aharonov-Bohm OscillationsReceived 28 June 2002; published 29 October 2002 We have probed the magnetic field dependence of the electron phase coherence time τφ by measuring the Aharonov-Bohm conductance oscillations of mesoscopic Cu rings. Whereas τφ determined from the low-field magnetoresistance saturates below 1 K, the amplitude of Aharonov-Bohm h/e oscillations increases strongly on a magnetic field scale proportional to the temperature. This provides strong evidence that a likely explanation for the frequently observed saturation of τφ at low temperature in weakly disordered metallic thin films is the presence of extremely dilute magnetic impurities. © 2002 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevLett.89.206804
DOI:
10.1103/PhysRevLett.89.206804
PACS:
73.23.-b, 71.10.Ay, 73.20.Fz, 73.50.-h
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