Defects in amorphous ferromagnets: Effects of ion implantation

Abstract

The effect of boron implantation on the magnetic properties of Fe 85B15Ni2 amorphous alloys has been investigated. The magnetization of thin film samples (3800 Å) obtained by rf sputtering has been studied before and after implantation of 1% atomic boron by using a SQUID magnetometer with magnetic fields up to 2 T. In this highly magnetostrictive material (λ≅30 ppm) the saturation process and coercive field are presumably dominated by the stress field due to the defect structure. Our analysis of the saturation process reveals that the vacancies introduced by boron implantation transform at room temperature into more stable defects: linear defects. These results are compared with computer simulations and model structures of amorphous metals.