Phase transition and extended X-ray absorption fine structure of melt-spun amorphous Fe100−xYx alloys

The phase diagram and local structure of melt-spun amorphous (a-) Fe100−xYx (22⩽x⩽62) alloys were investigated using AC and DC magnetic and extended X-ray absorption fine structure (EXAFS) measurements. The a-Fe–Y system shows reentrant spin glass (RSG) behavior for 42⩽x⩽58 and spin glass (SG) behavior for 60⩽x. Two SG transition temperatures, Tg and Tf, were obtained in the RSG state. The Tg, Tf and Curie temperature TC decrease with increasing x, and the TC and Tg vanish at x=60. A new magnetic phase diagram for the melt-spun a-Fe100−xYx alloys was obtained from magnetic measurements for higher Y concentration. The magnetic states of the a-Fe100−xYx alloys change remarkably around x=60 and an EXAFS study revealed that the average atomic distance between nearest-neighboring Fe atoms changes at approximately x=60.