NANO-CRYSTALLITE FE3C WITH GIANT MAGNETIC COERCIVITY IN SIO2

Fe-57 and C-12 ions were implanted at room temperature into single cry stal SiO2 with energies yielding approximately the same calculated ran ges. The energies were 60 and 20 keV, respectively for Fe-57 and C-12 and their corresponding doses were 5x10(16) and 2x10(17) at/cm(2). The cementite Fe3C was formed after annealing at 650 degrees C with a siz e of about 7 nm. Magnetic coercive forces of 900 and 800 Oe were obtai ned at RT and 80 K, respectively. An explanation for such a strong coe rcivity is suggested.