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Magnetic vortices in thin ferromagnetic films possess a core with out-of-plane magnetization whose polarity can be manipulated by magnetic fields or currents for technological applications. Here, the authors demonstrate local control of the core polarity in NiFe films via an imprinted maze domain pattern.

Chiral coupling between neighbouring magnetic domains is used in domain-wall racetracks to realize various all-electric logic operations by cascading the gates.

In this work, researchers show how laser annealing is used to create complex 2D gradients in magnetic properties, which can steer spin waves and domain walls. This fast, maskless method enables the development of next-generation computing devices.

Arranging nanomagnets into a two-dimensional lattice provides access to a rich landscape of magnetic behaviours. Control of the interactions between the nanomagnets after fabrication is a challenge. Here, Yun et al demonstrate all-electrical control of magnetic couplings in a two-dimensional array of nanomagnets using ionic gating.

Artificial spin ice formed of nanomagnets arranged on a lattice mimics frustrated magnetism seen in condensed matter. By controlling magnetic interactions, theoretically predicted phase transitions are now observed in artificial kagome-lattice spin ice.

Recently, periodic arrays of thermally active nanomagnets with bistable magnetization have been built which mimic the behaviour of frustrated magnets and model Ising systems. Here, the authors use muon spin relaxation to evidence thermodynamic phase transitions in an artificial kagome ice system.

The long-range magnetic order in an artificial crystal that exhibits emergent ferrotoroidicity on the mesoscale can be manipulated by an effective magnetic vortex field that is generated by a scanning process with a magnetic tip.

An array of nanomagnets in a kagome lattice structure should support the creation and separation of oppositely charged monopoles, which are connected by Dirac strings of flipped dipoles. And indeed, such monopoles and their Dirac strings can be observed at room temperature.

A new non-destructive spectroscopic method, ptychographic X-ray linear dichroic orientation tomography, is described, allowing the intragranular and intergranular characterization of extended polycrystalline and non-crystalline materials in three dimensions with nanoscale spatial resolution.

An artificial spin ice, containing two types of nanomagnets, can perform reservoir computing with minor magnetic field loops and spin wave spectra acting as inputs and outputs, respectively.

A non-invasive Streptococcus pneumoniae strain induces a unique NF-κB signature response in epithelial cells that requires the histone demethylase KDM6B. Modulation of KDM6B can interchange the host response to non-invasive and invasive pneumococcal strains, demonstrating the biological role of KDM6B in cellular responses during infection.

A human SARS-CoV-2 challenge study in individuals without previous exposure to the virus or vaccines provides detailed profiles of local and systemic epithelial and immune cell response dynamics over time and infection status.

Artificial spin ice structures can be designed that allow for the induction of thermal fluctuations, with dynamics that depend on the material and the lattice geometry.

A structurally chiral two-dimensional array of nanomagnets is shown to thermally relax its magnetization by rotation in a preferential direction, behaving as a magnetic ratchet.

Magnetic ordering in two-dimensional arrangements of nanomagnets can be repeatedly obtained by annealing an artificial spin ice.

A micromachine less than 100 micrometres across, made of arrays of nanomagnets on hinged panels, is encoded with multiple shape transformations  and actuated with a magnetic field.

Artificial spin-ice promises a means of probing dynamics in frustrated systems, but samples typically only shift between low-lying energy states under an external field. Exploring the energy landscape is now possible, through exquisite control over the thermal fluctuations of mesoscopic magnetic dipoles.

Nicholas Feasey and colleagues report whole-genome sequence analysis of 675 isolates of Salmonella enterica serovar Enteritidis from 45 countries. They find evidence for a global epidemic clade associated with enterocolitis and two novel clades restricted to distinct regions of Africa and associated with invasive disease.

Aleksandr Kurenkov and colleagues demonstrate nanomagnet arrays with out-of-plane anisotropy that spontaneously order at room temperature. This system offers a new platform for unconventional computing through tunable dynamics.

Both extrinsic and intrinsic factors determine the properties of ferroic materials and are difficult to disentangle. This study on artificial crystals of planar nanomagnets with well-defined, tuneable magnetic interactions unveils the intrinsic correlations between microscopic interactions and macroscopic properties such as the domain size and morphology or the domain-wall mobility.

Magnetic metamaterials can be designed to provide models of frustrated systems that allow theoretical predictions to be experimentally tested. Here the authors realise a 2D XY model with dipolar interactions and find behaviour consistent with predictions of a low-temperature ordered state.

Artificial spin ices are metamaterials displaying fascinating phenomena arising from the collective behaviour of nanoscale magnets. We review recent developments in terms of emergent magnetic monopoles, phase transitions, dynamics and geometries, and discuss future directions for research and potential applications.

Three-dimensional structures of vortex loops in a bulk micromagnet GdCo₂ have been observed using X-ray magnetic nanotomography. The cross-section of these loops consists of a vortex–antivortex pair stabilized by the dipolar interaction.

Knowledge and control of the dynamic response in micromagnetic configurations is important both for understanding their fundamental properties and for their use in technological applications. Pump–probe magnetic laminography now unveils the evolution of the magnetization in a three-dimensional system with nanoscale resolution.

Techniques exist for imaging the magnetization patterns of magnetic thin films and at the surfaces of magnets, but here hard-X-ray tomography is used to image the three-dimensional magnetic structure within a micrometre-sized magnet in the vicinity of Bloch points.

A single dose of the ChAdOx1 nCoV-19 vaccine elicits antibodies and cytokine-producing T cells that might help control or prevent SARS-CoV-2 infection.