Stability of information in Bloch line memories

The wall state stability of magnetic bubbles in ferrimagnetic as-grown garnet films suitable for Bloch line memory applications is investigated in order to predict the stability of vertical Bloch line pairs. In the experiment (1, 0) and (0, 2) bubbles are subjected to fast bias pulses (15-ns width) and to an in-plane field. It is found that the winding line pair present in a (0, 2) bubble can be annihilated, resulting in a (1, 0) final state. On the other hand, a (1, 0) bubble can be switched into a (0, 2) bubble with different experimental conditions. These nonconservative switching processes are in most cases irreversible. However, the switching probability never reaches 100%. An interpretation of the annihilation mechanism is given, and the consequences for devices are discussed