Modelling strain distributions in ion-implanted magnetic bubble materials

Abstract

The detailed properties of strain distributions in Ne+, B+, and He+ implanted magnetic bubble garnet materials are accounted for by calculating the nuclear energy loss as a function of depth. The calculation is based on stopped ion distributions for ZnS, with suitable corrections made for differences in material density. The constant of proportionality K between strain and nuclear energy loss, and the density ratio l are determined for each ion by comparing calculated strain distributions with experimental results obtained previously using an x-ray diffraction technique. It is found that K is roughly the same for all three ions, 0.016±0.003 (eV/Å3)−1, and that the average value l = 0.79±0.08 is consistent with the actual density ratio l = 0.72. Good agreement is found in additional examples of both single and multiple implants (±10% relative error). Finally, a procedure for selecting the incident energies and dosages required to produce a uniformly strained layer for bubble device applications is described, and then demonstrated by achieving a 0.4-um-thick layer with (1.07±0.09)% strain, using a double B+ implant.