  The increasing need to store large amounts of information with an
ultra-dense, reliable, low power and low cost memory device is driving
aggressive efforts to improve upon current perpendicular magnetic recording
technology. However, the difficulties in fabricating small grain recording
media while maintaining thermal stability and a high signal-to-noise ratio
motivate development of alternative methods, such as the patterning of magnetic
nano-islands and utilizing energy-assist for future applications. In addition,
both from sensor and memory perspective three-dimensional spintronic devices
are highly desirable to overcome the restrictions on the functionality in the
planar structures. Here we demonstrate a three-dimensional magnetic-memory
(magnetic page memory) based on thermally assisted and stray-field induced
transfer of domains in a vertical stack of magnetic nanowires with
perpendicular anisotropy. Using spin-torque induced domain shifting in such a
device with periodic pinning sites provides additional degrees of freedom by
allowing lateral information flow to realize truly three-dimensional
integration.
