Magnetite films grown directly on organic semiconductor layers

Magnetite (Fe₃O₄) films were grown directly on thin layers of two organic semiconductors (p-conjugated oligomers), 8-hydroxyquinoline aluminium (Alq₃) and sexitiophene (T6) by pulsed electron beam deposition, also called channel spark ablation (CSA), for which spin injection effects have been demonstrated at low and room temperatures. The room temperature ferromagnetism for both kind of films found by magneto-optical Kerr rotation (MOKE) and SQUID methods is observed. This represents the high quality films of magnetite as spin polarized top electrodes in organic based spintronic devices. Micro Raman spectroscopy confirms pure magnetite phase with the 300 cm^-1, 540 cm^-1 and 670 cm^-1 characteristic peaks for films deposited on both MgAl₂O₄ and organics. The atomic force microscopy indicated that the roughness of the magnetite films deposited on organic layers can be as low as the roughness of the glass or glass/ITO substrates. Finally the current injection of the magnetite film at the Fe₃O₄/Alq₃ interface is checked.