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

Abstract The phase diagram and local structure of melt-spun amorphous (a-) Fe 100− x Y x (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, T g and T f , were obtained in the RSG state. The T g , T f and Curie temperature T C decrease with increasing x , and the T C and T g vanish at x =60. A new magnetic phase diagram for the melt-spun a-Fe 100− x Y x alloys was obtained from magnetic measurements for higher Y concentration. The magnetic states of the a-Fe 100− x Y x 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.