Abstract
We have investigated the magnetic behaviors of the array of NiFe/IrMn rings, where a remarkably asymmetrical, kinked hysteresis loop has been observed in the sample. The kinked hysteresis loop has been attributed to the magnetization reversal, which starts from a single domain state to an opposite single domain state on one side of the loop, and takes place via the transition from a single domain state to a flux closure state and then into the opposite single domain state on the other side of the loop. This phenomenon is dramatically different from that of NiFe single layer rings. (C) 2003 American Institute of Physics.