MAGNETIC-PROPERTIES OF MECHANICALLY ALLOYED FE-CU

Magnetic properties of equiatomic FeCu alloys, obtained by mechanical alloying, were measured in a temperature range between 5 and 300K. The as-milled sample consists of a metastable fcc FeCu phase with a temperature dependence of magnetization which follows a T3/2 law. This metastable phase decomposes into Cu and Fe phases with annealing. After annealing at 820K, the magnetization value at low temperature is 30% smaller than the unannealed state. The Mossbauer spectrum obtained at room temperature shows a paramagnetic Fe phase with a relative resonant area of 30%. These results suggest that after this annealing process 30% of the iron is not in the ferromagnetic alpha phase but in a non-magnetic state (with vanishing atomic magnetic moment) or probably forming an antiferromagnetic gamma-Fe phase (which is paramagnetic at room temperature).