Effects of ion implantation on growth induced magnetic anisotropy in garnet films

Δ(Hk-4πMs) and lattice strain after annealing up to 1000°C for Ne+ implanted or H2+ implanted garnet films were investigated. While lattice strain completely vanished after 1000°C annealing, Δ(Hk-4πMs) after 1000°C annealing remained. Δ(Hk-4πMs) value increased in proportion to ion dose in low dose range and saturated to about 1900 Oe, which coincided with the growth-induced anisotropy field for as-grown films. The critical ion dose, at which Δ(Hk-4πMs) saturated, was approximately 200 keV 5×10¹⁴/cm²+ 80 keV 1.33×10¹⁴/cm²for Ne+ implantation and 70 keV 1×10¹⁷/cm²+ 35 keV 4.5×10¹⁶/cm²for H2implantation, respectively. Δ(Hk-4πMs) change for "re"-implanted films (which received additional implants after implantation with dose 200 keV 5×10¹⁴Ne+/cm²+ 80 keV 1.33×10¹⁴Ne+/cm²and subsequent annealing) increased less with lattice strain than that for as-implanted films. The difference in Δ(Hk-4πMs) change between as-implanted and "re"-implanted films approximately coincided with Δ(Hk-4πMs) value after the as-implanted films were annealed at 1000°C.