STRUCTURE OF C-STABILIZED FCC FE ON DIAMOND - EPITAXIAL-GROWTH OF AUSTENITE

Fe films were grown on single-crystal diamond substrates and the struc ture and chemistry of the Fe near neighbor environment was studied. It was observed that the Fe is in a metastable fee structure after a 350 degrees anneal, and a compression of the lattice in the plane of the surface of 1 +/- 0.6% was obtained by comparing low-energy electron di ffraction and extended x-ray absorption fine-structure results. Auger- electron spectroscopy shows that C begins diffusing into the fee Fe la ttice at approximately 200 degrees C. It was observed that the C signa l saturates at the equivalent of 1 atom/unit cell in the Fe film, and that the C atoms reside in the octahedral site, as expected for an aus tenite structure.