QUANTUM TUNNELING ACROSS A DOMAIN-WALL JUNCTION

In this article, we discuss a system that is appropriately called a domain-wall junction (DWJ). The DWJ is a close analog of the Josephson junction with respect to the usefulness of both systems in studying switching by thermal activation (TA) and by quantum tunneling (QT). We will show through theoretical analysis that it is within our means to fabricate a DWJ that should exhibit switching via quantum tunneling of magnetization. We further lay out experimental procedures for looking for quantum tunneling of magnetization in a DWJ; these procedures are based upon those used in observing macroscopic quantum tunneling in Josephson junctions. Two examples of DWJ's have been recently made that apparently show a crossover from TA to QT.