Ion irradiated modifications on magnetostrictive thin films

研究了Ar离子辐照的R-Fe(R：Tb，Sm)薄膜的磁致伸缩特性。薄膜样品是用磁控溅射法制备的。薄膜成分为Tb_lt；36&gt；Fe_&lt；&gt；和Sm_&lt；27&gt；Fe_&lt；73&gt；具有非晶态结构。沉积后，用10keV、2.7~8.0×10^~(-1)A/m^2的Ar离子辐照薄膜样品，剂量为1×10^~(-1)~2~(-1)离子/m^2。随着离子电流密度的增加，薄膜的磁致伸缩磁化率降低5.5×10~(-1)~(-1)&gt；A/m^2，大电流密度在7.0×10~(-1)&lt；-1~gt；A/m^2以上，磁致伸缩磁化率提高。当离子电流密度达到5.5×10~(-1)~(-1)A/m~2时，Fe_&lt；73&gt；随着离子电流密度的增大而增大。这是由于低电流密度下Ar离子辐照引起的压应力增大和高电流密度辐照时温度升高引起的应力松弛所致。研究发现，辐照损伤和热退火效应等竞争性因素引起的应力对薄膜的磁性能有很大的影响。

Magnetostrictive properties of Ar ion-irradiated R-Fe(R : Tb, Sm) thin films were studied with respect to internal 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 with Ar ions at 10 keV, 2.7-8.0×10^<-1> A/m^2 and doses of 1x10^<22> ions/m^2. Magnetostrictive susceptibility of the Tb_<36>Fe_<64> film decreased with increasing ion current density by 5.5x10^<-1> A/m^2, however, improved with high current density above 7.0 x10^<-1> A/m^2. Magnetostrictive susceptibility of Sm_<27>Fe_<73> increased with increasing ion current density up to 5.5 x10^<-1> 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.