Annealing of Magnetic Properties of Ion Implanted Garnet Epitaxial Films

Annealing characteristics are reported for two epitaxial garnet materials: Y1Eu1.85Yb.15Al1.1Fe3.9O12 and YGdTmGa.8Fe4.2O12 on (111) Gd3Ga5O12. Ion implantation has been used to suppress hard bubbles in these materials. The changes observed in the magnetic properties during annealing are due to removal of the ion implantation effects, removal of growth induced anisotropy and changes in the magnetization, 4πMs. The films used were ∼6μm thick and supported ∼6μm bubbles at room temperature. Three parameters were measured after 30 minute anneals in O2: the minimum bias field Hm for bubble collapse, the bias field collapse range ΔH, and the demagnetized domain strip width, from which 4πMs, the material length l, and the domain wall energy σw were determined. Hydrogen ion implantation at 25–50 keV typically increases Hm by several oersteds and decreases ΔH from ∼25–40 Oe down to ∼1 Oe. Annealing of the ion implantation effects was observed in the range 600 to 1000°C. The implantation‐induced increase in Hm disa...