Effect of Residual Stress Induced by Ar Ion Irradiation on Magnetostriction of R-Fe(R: Tb, Sm) Thin Film

Abstract

Magnetostrictive properties of Ar ion irradiated R Fe(R: Tb, Sm) thin films were studied with respect to residual stress. Film samples were prepared by a magnetron sputtering. The film composition was Tb 36 Fe 64 and Sm 27 Fe 73 with amorphous structures. After the deposition, film samples were irradiated by Ar ions with an energy of 10 keV and a current density of 27 80× 10 -2 A/m 2 up to 1×10 22 ions/m 2 . Magnetostrictive susceptibility of the Tb 36 Fe 64 film decreased with increasing ion current density by 55×10 -2 A/m 2 , however, improved with high current density above 70×10 -2 A/m 2 . Magnetostrictive susceptibility of Sm 27 Fe 73 increased with increasing ion current density up to 55×10-2 A/m 2 . This was caused by increase of compressive stress induced by Ar ion irradiation with low current density and stress relaxation by increased temperature during irradiation with high current density. The magnetic properties were found profoundly influenced by stresses induced by competitive factors such as irradiation damage and thermal annealing effect.

Effect of Bias Sputtering on Magnetostrictive Property of Sm-Fe Thin Film

“…The composition of the Sm-Fe lms were about Sm 22 Fe 78 determined by WDX. This composition on Sm-Fe system is presumed to form two phase alloy include Sm 2 Fe 17 phase and SmFe 3 phase by phase diagram.…”

“…21) Takeuchi et al suggested that the magnetostrictive susceptibility of the thin lms increased with decreasing magnetic anisotropy energy due to increasing the compressive stress. 22) Accordingly, this improve of the dλ/dH can be caused by a development of the in-plane magnetic anisotropy induced by the increase of compressive stress.…”

Growth of Bi-Ti-O particles by ion implantation

“…Furthermore, magnetostrictive materials forms single domain by making it to amorphous. The domain structure of the magnetostrictive amorphous consists mainly of a single domain inner core with the magnetization [3]. However, the magnetostrictive materials actually used are not complete amorphous but contain the crystalline phase, which becomes the nucleus of the domain formation.…”