Large magnetostrictive susceptibility in Tb- FeCo/FeCo multilayers

Abstract

[Tb(Fe0.55Co0.45)1.5/Fe]n and [Tb(Fe0.55Co0.45)1.5/(Fe0.5Co 0.5]n multilayers were fabricated by rf-magnetron sputtering from composite targets. Magnetostriction was measured using an optical deflectometer. The as-deposited films showed a soft magnetic and magnetostrictive character, with a coercive field ?0Hc=5 mT and a parallel magnetostrictive susceptibility ????=d?par;/d(?0H) =1.4??10-2 T-1 . This magnetostrictive softness was strongly improved by heat treatments: the magnetostrictive susceptibility attains the huge value of 5??10-2 T-1 in applied field of 6 mT. The low-field dependence of the magnetostrictive susceptibility and their technical characters are described in detail. ?? 2001 American Institute of Physics.