Spin-Dependent Conductance in Co/C60/Co/Ni Single-Molecule Junctions in the Contact Regime

The spin-dependent conductance in Co/C60/Co/Ni single-molecule magnetic tunnel junctions has been measured by combining spin-polarized scanning tunneling spectroscopy and current-displacement measurements using an ultrahigh vacuum low temperature scanning tunneling microscope (STM) at 5 K. With an electrical contact between molecule and electrodes, the measured junction conductance is 0.02-0.13 G0 in the low-conductance state and 0.12-0.76 G0 in the high-conductance state, respectively. The investigated single-molecule junctions exhibit large tunnel magnetoresistance (TMR) ratios higher than −60%. A variation of TMR from −63% to −94% has been observed due to different Co/Ni electrodes.