ION-IMPLANTATION PHENOMENA RELATED TO HARD BUBBLE SUPPRESSION IN MAGNETIC-BUBBLE YIG

Some aspects of the hard bubble suppression mechanism have been investigated in LPE grown magnetic bubble garnets, (Y1.65Sm 0.18Lu0.21Ca0.96) (Fe0.96Ge 4.04) O12. Following implantation of neon ions at a standard suppression dose of 5*1014 cm-2 collapse field measurements indicate effective hard bubble suppression. For this dose however, 57Fe Mossbauer spectra indicate the pressure of a non-magnetic surface layer while X-ray diffraction traces and alpha particle backscattering measurements indicate that the layer is structurally disordered. These observations are inconsistent with the capping layer model of hard bubble suppression. Implantation of nitrogen ions resulted in similar hard bubble suppression but produced a totally different form of radiation damage. Axial channelling of 800 keV nitrogen ions along the (111) direction is observed.