Magnetic properties and crystallization of amorphous Fe90 − xMnxZr10 alloys with x = 0–15

A systematic investigation of the Curie temperature TC, magnetic moment μ¯ and spin-glass-like behavior of amorphous Fe90 − x MnxZr10 (x = 0, 4, 6, 10 and 15) has been performed by magnetization measurements. The magnetic moment and the Curie temperature of amorphous Fe-Mn-Zr alloys are found to decrease monotonically with increasing Mn concentration. The decrease of μ¯ and TC with x may be due to the antiparallel coupling between the Fe and Mn atoms. It is found that there is a transition of ferromagnetic to spin-glass phase at low temperature. The spin freezing temperature Tf is found to increase with increasing Mn concentration from about 32 K for x = 0 to about 62 K for x = 15. The thermomagnetic curves measured at heating and cooling temperature on the sample crystallized from amorphous Fe84Mn6Zr10 alloy show an irreversible magnetic transition. This anomalous phenomenon can be attributed to the transition of the ferromagnetic α-(Fe,Mn) phase to the nonmagnetic γ-(Fe,Mn) phase for heating at about 1000 K and from γ-(Fe,Mn) phase to α-(Fe,Mn) phase for cooling at about 570 K.