<研究ノート>強磁性電極に架橋した単分子の磁気抵抗特性

Abstract

We have investigated the spin dependent electrical transport through Ni/benzenedithiol(BDT)/Ni single molecule junctions fabricated with the mechanically controllable break junction (MCBJ) method. By measuring the junction resistance under different magnetic field strength, magnetoresistive properties of Ni/BDT/Ni junctions are observed at cryogenic temperatures. The junction resistance shows a hysteresis against the field strength, indicating that the electronic transport across Ni/BDT/Ni depends on the relative orientation of the magnetization of Ni electrodes. Thus, the Ni/BDT/Ni works as a single-molecule spin valve. The observed magnetoresistance is larger than that of conventional spin valves in which nonmagnetic layer are used as a tunnel barrier. This result is consistent with theoretical studies which predict a large magnetoresistance for the junctions of π-conjugated molecules.