Temperature stable self-biasing bubbles in double layer films

One of the most important problems for a self-biasing bubble (SBB) device is the temperature stability of the SBB diameter. The temperature dependence of the SBB diamater was calculated on the basis of the force stability condition of the SBB and proved to be proportional to the temperature dependence of the characteristic length of the top layer. The proportional coefficient depended on h/l and that was more than -2.7. The smallest value of temperature sensitivity was +0.8%/°C in the system of (YCaEuYb)
3
GeIG/ (EuEr)
3
GaIG. No hard bubbles were observed in this self-biasing double layer film and the mobilities of the SBB were similar to those of the usual single layers. And SBB were generated, propagated and detected by means of the usual drive technique (T-Bar permalloy circuits) without any bias field, the operating margins were similar to those of the bubbles in the usual single layer films.