Dependence of read/write operations on uniaxial anisotropy constant in Bloch line memories

Characteristics of read/write (R/W) operations in Bloch line (BL) memory test structures have been investigated in order to find out which material characteristics of the magnetic garnet film have influence on the R/W margins. Two types of magnetic garnet films were investigated: one type has wide R/W margins, and the other has narrow R/W margins. The uniaxial anisotropy constant (Ku) of the magnetic garnet film with the wide R/W margins is twice as large as that of the film with the narrow R/W margins. It has been found that the stripe domain is easy to chop, and horizontal Bloch lines (HBLs) are easy to nucleate in the magnetic garnet film with the narrow R/W margins. It is thought that these phenomena come from the ease of the domain wall motion. Since the domain wall tends to move easily for small values of Ku, resulting in relatively easy domain chopping and HBL nucleation, the implication is that Ku should be increased in order to obtain wide R/W margins.