  Bistable nanomagnets store a binary bit of information. Exchange coupled
nanomagnets can increase the thermal stability at low dimensions. Here we show
that the antiferromagnetically (AFM) coupled nanomagnets can be highly stable
at low dimensions than that of the ferromagnetically (FM) coupled nanomagnets.
By solving stochastic Landau-Lifshitz-Gilbert equation of magnetization
dynamics at room temperature, we analyze the stability of the exchange coupled
nanomagnets in the presence of correlated, uncorrelated, and anti-correlated
noise. The results show that the correlated noise can make the stability of the
AFM coupled nanomagnets very high. Such finding will lead to very high-density
non-volatile storage and logic devices in our future information processing
systems.
