Magnetically ordered Fcc structure at the relaxed grain boundaries of pure nanocrystalline Fe

Pure Fe powders, milled down to 10 nm crystallite size, have been analyzed by a combination of Mössbauer spectroscopy, high resolution transmission electron microscopy, and magnetization measurements. After annealing the as-milled powders at 570 K for 1 hour, a new phase is identified with a hyperfine field of 21 T, a lower magnetic moment than bulk Fe, a magnetic order-disorder transition temperature of about 500 K, and a fcc crystal structure. It is tentatively interpreted as a new magnetically ordered phase of Fe. © 1998 The American Physical Society.

Pure Fe powders, milled down to 10 nm crystallite size, have been analyzed by a combination of Mössbauer spectroscopy, high resolution transmission electron microscopy, and magnetization measurements. After annealing the as-milled powders at 570 K for 1 hour, a new phase is identified with a hyperfine field of 21 T, a lower magnetic moment than bulk Fe, a magnetic order-disorder transition temperature of about 500 K, and a fcc crystal structure. It is tentatively interpreted as a new magnetically ordered phase of Fe.