Highly ordered C₆₀ films on epitaxial Fe/MgO(001) surfaces for organic spintronics

Hybrid interfaces between ferromagnetic surfaces and carbon-based molecules play an important role in organic spintronics. The fabrication of devices with well defined interfaces remains challenging, however, hampering microscopic understanding of their operation mechanisms. We have studied the crystallinity and molecular ordering of C-60 films on epitaxial Fe/MgO(001) surfaces, using X-ray diffraction and scanning tunneling microscopy (STM). Both techniques confirm that fcc molecular C-60 films with a (111)-texture can be fabricated on epitaxial bcc-Fe(001) surfaces at elevated growth temperatures (100-130 degrees C). STM measurements show that C-60 monolayers deposited at 130 degrees C are highly ordered, exhibiting quasi-hexagonal arrangements on the Fe(001) surface oriented along the [100] and [010] directions. The mismatch between the surface lattice of the monolayer and the bulk fcc C-60 lattice prevents epitaxial overgrowth of multilayers. (C) 2012 Elsevier B.V. All rights reserved.