Figure 5: Kondo effect and magnetoconductance measurements at 4 K for samples with different molecular thicknesses of CoPc.
From: Spin doping using transition metal phthalocyanine molecules
(a) Normalized resistivity versus temperature in log-2 scale. Open symbols correspond to CoPc nominal thicknesses of 10, 20, 30, 40 and 50 Å. Black solid squares corresponds to the 99.99% pure 200 Å thick bare-gold film. (b) Universal Kondo plot of the normalized resistivity divided by respective residual resistivity, 
, against normalized temperature, 
, for all thicknesses. Solid line represents the exact numerical renormalization group (NRG)26,27 solution predicted for a S=1/2 system of diluted magnetic impurities. TK was determined to be 6.6±0.2 K. (c) Determined ρ0 as a function of Tmin for the different CoPc thickness. Error bars were determined from the s.d. of the fittings. (d) Magnetoconductance at 4 K for CoPc nominal thicknesses of 10, 20, 30, 40 and 50 Å. Solid black squares corresponds to the 200 Å thick gold reference film. Solid lines are fits to the Hikami, Larkin and Nagaoka (HLN) theory30 for the magnetoconductance of thin films. The phase coherence lengths are determined to be 645, 272, 102, 106, 59 and 40 nm for CoPc thicknesses of 0, 10, 20, 30, 40 and 50 Å, respectively.
