Hard bubble suppression and controlled state generation of one micron bubbles in ion-implanted garnet films

Hard bubble suppression with proton and neon implantation was achieved in one micron Eu.8Tm2.2Ga.5Fe4.5O12films. The dose and energy required in these one micron bubble films are similar to that required in five micron bubble films, despite the fact that the one micron films have larger uniaxial anisotropy to be overcome with the induced magnetostriction. In addition, controlled state generation (for bubble lattlce device applications) has been demonstrated in the proton implanted samples using two different techniques. The first technique, using a combination of an in-plane field and a critical velocity, is identical to what Hsu has reported with five micron bubbles, except that the in-plane field required in this case is 20 to 40% larger. The second technique, using DC and AC in-plane fields only without any field gradient, has also been shown. In the case of conversion from a bubble that propagates at an angle from the field gradient to one that propagates along the field gradient, a DC in-plane field of 300 Oe is needed. While in the reverse case, an AC in-plane field of 100 Oe or so is necessary.