  Two-dimensional arrays of magnetically coupled nanomagnets provide a
mesoscopic platform for exploring collective phenomena as well as realizing a
broad range of spintronic devices. In particular, the magnetic coupling plays a
critical role in determining the nature of the cooperative behaviour and
providing new functionalities in nanomagnet-based devices. Here, we create
coupled Ising-like nanomagnets in which the coupling between adjacent
nanomagnetic regions can be reversibly converted between parallel and
antiparallel through solid-state ionic gating. This is achieved with the
voltage-control of magnetic anisotropies in a nanosized region where the
symmetric exchange interaction favours parallel alignment and the antisymmetric
exchange interaction, namely the Dzyaloshinskii-Moriya interaction, favours
antiparallel alignment. Applying this concept to a two-dimensional lattice, we
demonstrate a voltage-controlled phase transition in artificial spin ices.
Furthermore, we achieve an addressable control of the individual couplings and
realize an electrically programmable Ising network, which opens up new avenues
to design nanomagnet-based logic devices and neuromorphic computers
