  A cluster composed of a few magnetic atoms assembled on the surface of a
nonmagnetic substrate is one suitable realization of a bit for future concepts
of spin-based information technology. The prevalent approach to achieve
magnetic stability of the bit is decoupling the cluster spin from substrate
conduction electrons in order to suppress spin-flips destabilizing the bit.
However, this route entails less flexibility in tailoring the coupling between
the bits which is ultimately needed for spin-processing. Here, we show using a
spin-resolved scanning tunneling microscope, that we can write, read, and store
spin information for hours in clusters of only three atoms strongly coupled to
a substrate featuring a cloud of non-collinearly polarized host atoms, a so
called non-collinear giant moment cluster (GMC). The GMC can be driven into a
Kondo screened state by simply moving one of its atoms to a different site.
Owing to the exceptional atomic tunability of the non-collinear substrate
mediated Dzyaloshinskii-Moriya interaction, novel concepts of spin-based
information technology get within reach, as we demonstrate by a logical scheme
for a four-bit register.
