Rapidly quenched Fe_xTa_100-x alloys

Authors

C.L. Chien, Johns Hopkins University, Baltimore, Maryland
Sy_Hwang Liou, University of Nebraska-LincolnFollow
B.K. Ha, Johns Hopkins University, Baltimore, Maryland
K.M. Unruh, Johns Hopkins University, Baltimore, Maryland

Date of this Version

April 1985

Comments

Published by American Institute of Physics. J. Appl. Phys. 57, 3539 (1985). ©1985 American Institute of Physics. Permission to use. Journal home page = http://jap.aip.org/jap/.

Abstract

Binary alloys of Fe_xTa_100-x were made by high-rate sputtering. A sharply defined boundary separates the composition ranges in which crystalline alloys (93 ≤ x ≤100) and amorphous alloys (15 ≤ x ≤ 90) are formed. The amorphous alloys with Fe concentrations up to the threshold of x_c ≈ 65 are nonmagnetic. For the samples with x > x_c, the magnetic ordering temperature (T_c) varies monotonically with Fe content to 200 K for a-Fe₉₀Ta₁₀. However, the crystalline alloys, with slightly higher Fe content, are strongly ferromagnetic. Their T_c's are several hundred degrees higher, accompanied by large increases in magnetic moment and hyperfine fields. This discontinuity illustrates the sensitivity with which the magnetic properties of Fe-transition metal alloys depend on structure. In contrast, no discontinuity has been observed in Co-Ta alloys.