Temperature-dependent magnetic properties of mechanically alloyed Al-1 at% Fe

High-temperature magnetization studies on mechanically alloyed Al-1 at% Fe samples milled for 30, 300 and 1000 min show a deviation from conventional ferromagnetic behaviour. The variation in the initial permeability and coercivity is dependent on both size and paramagnetic content. The Brillouin functions fitted to experimental curves are closest for a function with J=1/2 for the 30 and 1000 min milled samples. The effective spin is seen to be much less for the sample milled for 300 min. The observed deviation is qualitatively related to locking of surface spins through nearest-neighbour antiferromagnetic coupling