Oscillating spatial dependence of domain memory in ferromagnetic films mapped via x-ray speckle correlation

Abstract

Magnetic domain memory (MDM) is observed in a Co/Pd ferromagnetic film when subject to exchange couplings with an IrMn antiferromagnetic layer. Our study uncovers the spatial and field dependence of the MDM at the nanoscopic scale. We found the degree of MDM to be extremely high (over 92%) at the scale of the domain periodicity, about 400 nm, and in the coercive region of the magnetization cycle, at about 1000 Oe. Furthermore, we observed an unusual spatial oscillation in the MDM, revealing a superstructure in the memory correlation at about 1.5 \ensuremath{\mu}m.