Magnetic building blocks in two dimensions: Artificial magnetic structures can offer a variety of functionalities in spintronics devices. Luo et al. engineered magnetic domains in Pt/Co/AlO _x trilayers that had alternating in-plane and out-of-plane magnetizations. The regions interacted laterally through the so-called Dzyaloshinskii-Moriya interaction, which determined the relative sign and orientation of the magnetization in adjacent domains. Using the coupling between the domains, the researchers were able to engineer more-complex magnetic structures such as skyrmions and frustrated magnets. Science , this issue p. 1435

Patterned electrodes on a piezoelectric substrate are demonstrated to produce a localized strain of sufficient magnitude to control the magnetic anisotropy of a Ni island. Strain-induced magnetic anisotropy was measured using the magneto-optical Kerr effect, and the measured shifts in magnetic anisotropy were consistent with strain predicted using linear finite element analysis. This approach overcomes the effect of the substrate clamping the in-plane strain and should be scalable to thin films. This approach represents a key step toward realizing the next generation of strain mediated magneto-electric magnetic random access memory devices with low writing energy and high writing speed.

Nanomagnetic logic, which makes use of arrays of dipolar-coupled single-domain nanomagnets for computation, holds promise as a low-power alternative to traditional computation with CMOS. Beyond the use of nanomagnets for Boolean logic, nanomagnets can also be exploited for nondeterministic computational schemes such as edge detection in images and for solving the traveling salesman problem. Here, we demonstrate the potential of arrangements of thermally active nanomagnets based on artificial spin ice for both deterministic and probabilistic computation. This is achieved by engineering structures that follow particular thermal relaxation pathways consisting of a sequence of reorientations of magnet moments from an initial field-set state to a final low-energy output state. Additionally, we demonstrate that it is possible to tune the probability of attaining a particular final low-energy state, and therefore the likelihood of a given output, by modifying the intermagnet distance. Finally, we experimentally demonstrate a scheme to connect several computational building blocks for complex computation.