Observation of a large spin-dependent transport length in organic spin valves at room temperature

The integration of organic semiconductors and magnetism has been a fascinating topic for fundamental scientific research and future applications in electronics, because organic semiconductors are expected to possess a large spin-dependent transport length based on weak spin-orbit coupling and weak hyperfine interaction. However, to date, this length has typically been limited to several nanometres at room temperature, and a large length has only been observed at low temperatures. Here we report on a novel organic spin valve device using C-60 as the spacer layer. A magnetoresistance ratio of over 5% was observed at room temperature, which is one of the highest magnetoresistance ratios ever reported. Most importantly, a large spin-dependent transport length of approximately 110 nm was experimentally observed for the C-60 layer at room temperature. These results provide insights for further understanding spin transport in organic semiconductors and may strongly advance the development of spin-based organic devices.