Researchers from Osaka Metropolitan University and Osaka City University have succeeded in measuring spin transport in a thin film of specific molecules - a material well-known in organic light emitting diodes (OLEDs) - at room temperature.
They found that this thin molecular film has a spin diffusion length of approximately 62nm, a length that could have practical applications in developing spintronics technology. In addition, while electricity has been used to control spin transport in the past, the thin molecular film used in this study is photoconductive, allowing spin transport control using visible light.
The research group, led by Professors Eiji Shikoh and Yoshio Teki of the Osaka Metropolitan University Graduate School of Engineering, has successfully measured spin transport, at room temperature, in a thin film of naphthyl diamine derivative: N,N′-Bis(naphthalen-1-yl)-N,N′-bis(phenyl)-2,2′-dimethylbenzidine (α-NPD).
To use spin transport to develop spintronics technology requires having a spin diffusion length in the tens of nanometer range at room temperature for accurate processing. The thin molecular film of α-NPD with a spin diffusion length of 62 nanometers - a long distance for molecular materials - was fabricated for this study by thermal evaporation in vacuum.
"For practical use, it will be necessary to uncover more details about spin injection and spin transport mechanisms through thin molecular films to control spin transport," noted Professor Shikoh. "Further research is expected to lead to the realization of super energy-efficient devices that use small amounts of power and have little risk of overheating."