The temperature and time dependence, in different magnetic fields, of the f
ield-cooled and zero-field-cooled magnetisation on ball-milled nanocrystall
ine Fe has been studied. The results indicate the existence, below about 70
K, of a disordered frozen magnetic state which is erased by applying an ex
ternal field H = 1000 Oe, favouring the ferromagnetic order. (C) 2001 Elsev
ier Science B.V. All rights reserved.