Investigation on the spin filtering properties of the organic molecules through single molecule conductivity measurement

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MCBJ (mechanically controlled break-junction) as a platform for measuring single molecule conductance and testing spin filtering properties of organic radical species was successfully built and tested. Substantial improvement in the instrumental setup compared to the preliminary stage was made to realize the single molecule conductance of organic molecule which has several order of magnitude smaller than the conductance of metal atoms. Whole the structure of the instrument and the operating program was revised to reduce vibration and electrical noise and a piezo element was introduced to make precise junction distance control. Junction fabrication method was also revised for better reproducibility. Solution cell and the mount was also installed to the instrument to allow solution state measurement for electrochemical gating. Performance of the instrument was examined with p-benzenedithiol as reference and the MCBJ instrument was able to reproduce the reported conductance. Further optimization on the operating speed of the instrument for statistical analysis and investigation on the actual single molecule conductance and spin filtering properties of organic radical species will be held in subsequent year.