MAGNETIZATION OF AMORPHOUS FE-0.82,B-0.18 AND FE0.90ZR0.10 COMPOUNDS WITH ADDITIONS OF TB

The addition of Tb to melt spun iron-boron or iron-zirconium compounds raises the magnetostriction to practically useful levels (greater tha n or equal to 450 ppm) at room temperature. The present work examines the corresponding compositional and temperature dependencies of the ma gnetization in Tb-x (Fe0.82B0.18)(1-x) for 0 less than or equal to x l ess than or equal to 0.5 and Tb-y (Fe0.90Zr0.10)(1-y) for 0 less than or equal to y less than or equal to 0.1. Increasing the Tb content in Fe-B compounds decreases the room-temperature magnetization towards a compensation point and lowers the Curie temperature T-c. In Fe-Zr comp ounds, Tb increases the room-temperature magnetization and raises T-c. Magnetic phase diagrams are presented for each group of compounds and exchange frustration effects identified by comparing the observed tem perature dependencies of the reduced magnetization with predictions fr om the Handrich mean field model. Only 3 at. % Tb in Fe-Zr is sufficie nt to annul exchange fluctuations, but in Fe-B compounds exchange frus tration persists throughout the compositional range.