Monitoring Ionic Diffusion from CoB in Molecular layers

We have studied the thermal diffusion of Boron in C
60
/CoB/C
60
trilayers using Polarised Neutron Reflectometry (PNR). Monitoring the diffusion of boron in carbon is a difficult problem using electron or X-ray based techniques. On the other hand, boron can be easily detected in neutron spectroscopy due to its strong absorbance. Comparing PNR measurements taken before and after in-situ annealing for 10 hours at 300°C shows significant changes in the nuclear and magnetic structure. Fits to the data suggest that Boron migrates from the CoB alloy into and through the adjacent 20nm C60 layers and aggregates at the very top and bottom interfaces of the trilayer. This demonstrates ionic diffusion in a fullerene layer, suggests that molecular thin films may be used for ionic-control of magnetism and as ionic reservoirs in ultra-thin electrical devices.