Vertical bloch line memory

The concept of chirality in magnetic domain walls is reviewed leading to a discussion of Vertical Bloch lines as a mechanism of chirality change. Their proposed use as a magnetic memory element is reviewed. The WRITE operation is outlined. A write gate is proposed that interfaces the major loop with the VBL containing stripes that comprise the minor loop. One transfer line is required and a five pulse sequence to write and a two pulse sequence to clear. The WRITE operation seems to be practical. Propagate in the minor loops (stripes) is the most unknown. Although the structures should work in principle, the operation has yet to be demonstrated. The READ operation seems very practical. A gate similar to the WRITE gate will work but only needs a three pulse sequence. The ultimate density is yet to be established. Because of the interface to the major loop which is bubble, the limiting spacing is four bubble diameters. Spacing along the stripe will hold the answer to the ultimate density. This spacing is yet to be demonstrated.