AFMカンチレバー

Controllable Gliders in a Nanomagnetic Metamaterial: MFM Reveals Magnetic “Snakes”

Artificial Spin Ice (ASI) has emerged as a fascinating platform for studying collective behaviour in interacting nanomagnets, with potential applications ranging from magnetic devices to neuromorphic computing. In this article, Arthur Penty, Johannes H. Jensen, Ida Breivik, Anders Strømberg, Erik Folven, and Gunnar Tufte demonstrate how a mobile magnetic structure — a “snake” glider — can be created and precisely controlled within a nanomagnetic metamaterial.

Inspired by the concept of gliders in Cellular Automata, the researchers use an evolutionary algorithm to discover a simple moving structure within a pinwheel Artificial Spin Ice system. The resulting snake can move through the nanomagnetic array under a global magnetic-field protocol, allowing controlled manipulation of magnetic textures on a scale of approximately 100 nm.

Artificial Spin Ice as a Platform for Information Processing

Artificial Spin Ice consists of interacting nanomagnets arranged in a two-dimensional lattice. These nanoscale magnetic elements can exhibit collective states and emergent behaviour, making ASI attractive for exploring unconventional approaches to information processing.

A key challenge is integrating information transformation, transmission, and storage into the same physical system. The snake glider introduced in this article addresses this challenge by providing a controllable magnetic structure that can move through the ASI lattice while retaining its functionality.

The researchers demonstrate that the snake can move either left or right depending on its orientation. Its motion is controlled through a sequence of in-plane magnetic fields, while simulations and experiments are used to investigate the mechanism responsible for the glider’s movement and its robustness against disorder.

NanoWorld MFMR for Magnetic Force Microscopy

Experimental investigation of the nanomagnetic structures was performed using NanoWorld POINTPROBE MFMR, a magnetic force microscopy AFM probe designed for magnetic imaging.

The NanoWorld MFMR was used for both writing the initial magnetic state and imaging the resulting magnetic structures. To initialise the snake, the MFM probe was used to write an approximately 1 µm magnetic line in the pinwheel Artificial Spin Ice while a 10 mT bias field was applied. The writing process was performed with the MFM probe in contact with the sample at a scan speed of 55 µm/s.

Fig. 5: Analysis of neighbour influence in the snake. Neighbour influence during (a) shrinking and (b) growth. The five insets illustrate how the highlighted magnet is influenced by its neighbours through their dipolar fields. The influence of a neighbour acting on a magnet is given by the resulting change in the magnet’s proximity to the switching astroid when considering the neighbour’s dipolar field. Positive influence values (blue) indicate an increased distance (stabilising) and negative values (red) indicate a decreased distance (destabilising). The centre legend shows the parallel (∥) and perpendicular (⊥) nearest neighbours, as well as the second nearest neighbours (2).

Following magnetic-field-driven evolution of the structure, the researchers used MFM to image the magnetic state after each applied field. Imaging was performed at remanence using a lift height between 55 and 60 nm and scan speeds between 50 and 55 µm/s. All experiments were conducted at room temperature.

These measurements allowed the researchers to directly observe how the magnetic texture evolved as the snake moved through the nanomagnetic array.

Imaging a Controllable Magnetic Texture

The experimental MFM results provide a direct view of the magnetic states underlying the glider behaviour. By repeatedly applying the field protocol and imaging the resulting configurations, the researchers could track the movement of individual snakes and investigate how their structure responds to the magnetic environment.

The experiments also demonstrated the robustness of the concept. Multiple snakes could be initialised within the same Artificial Spin Ice array while maintaining sufficient separation to avoid unwanted interactions. The researchers further investigated how fabrication disorder affects the movement of the gliders, finding evidence of self-correction and graceful degradation before motion eventually breaks down.

The combination of experimental MFM imaging and micromagnetic simulations provides a detailed picture of the mechanism behind the snake’s movement. This makes the approach particularly interesting for studying how local magnetic interactions can be harnessed to produce controlled, collective behaviour.

From Magnetic Gliders to Neuromorphic Computing

The snake glider provides more than a visually compelling magnetic structure. Because its position and movement can be controlled, it can act as a physical carrier of information within the Artificial Spin Ice substrate.

The researchers demonstrate how the glider can contribute to information transmission, storage, and transformation, potentially allowing these functions to be integrated into a single magnetic material. Such concepts could contribute to the development of ultra-low-power computing architectures based on nanoscale magnetic states rather than conventional electronic switching.

For this type of research, high-quality MFM probes are

essential for resolving and manipulating nanoscale magnetic structures. The NanoWorld POINTPROBE MFMR provides a dedicated solution for magnetic force microscopy, enabling both magnetic writing and high-resolution imaging of nanomagnetic systems.

The work by Penty and co-authors demonstrates how MFM can do more than simply characterise magnetic materials: it can become an experimental tool for exploring programmable magnetic textures, emergent behaviour, and new approaches to information processing.

Full citation:
Penty, A.; Jensen, J. H.; Breivik, I.; Strømberg, A.; Folven, E.; Tufte, G.
Controllable gliders in a nanomagnetic metamaterial.
Nature Communications 2025, 16, 7500.
DOI: 10.1038/s41467-025-62515-1

License: CC BY 4.0

Plant-Growth Synchronized, Acid Phosphatase-Responsive Lignin-Based Controlled Release Phosphorus Nanofertilizers

Developing smarter fertilizer systems that deliver nutrients when and where plants need them could help improve nutrient efficiency while reducing unnecessary losses to the environment. In this article, Alice Boarino, Nicola Carrara, Joaquin Clua, Nick Zahnd, Yves Poirier, and Harm-Anton Klok present a lignin-based nanofertilizer platform designed to respond to a biological signal associated with phosphate deficiency in plants.

The researchers developed tripolyphosphate (TPP)-cross-linked lignin nanoparticles engineered to release phosphorus in response to acid phosphatase. This enzyme is upregulated by plants under phosphate-starvation conditions, providing a mechanism for synchronizing nutrient release with plant demand. The lignin/TPP nanoparticles therefore combine a biodegradable polymer-based carrier with an enzyme-responsive release mechanism rather than relying on a conventional uncontrolled release process.

The nanofertilizers were prepared from aminated lignin and tripolyphosphate through ionic gelation followed by covalent cross-linking. The resulting nanoparticles were investigated to determine their structural and functional properties and to understand how exposure to acid phosphatase affects their stability. The authors found that phosphorus release was triggered by acid phosphatase activity and occurred together with nanoparticle disintegration, demonstrating the responsiveness of the lignin-based delivery system to the targeted enzymatic stimulus.

The biological experiments further demonstrated the potential of the nanoparticles as a phosphorus source for Arabidopsis thaliana. Treatment with lignin-TPP nanoparticles suppressed the growth inhibition and molecular responses normally associated with phosphate deficiency, supporting their potential as controlled-release nanofertilizers for plant growth and development.

Atomic force microscopy (AFM) was used to characterize the morphology and size distribution of the lignin-based nanoparticles. AFM imaging was performed in tapping mode using a NanoWorld PointProbe® NCSTR-50 AFM probe, an aluminum-coated silicon cantilever with a spring constant of 7.4 N/m and a resonance frequency of approximately 160 kHz.

For AFM analysis, nanoparticle dispersions were deposited onto cleaned silicon wafers and dried overnight at room temperature. Samples prepared in Milli-Q water were used to characterize nanoparticle dimensions, while dispersions in MES buffer were used to investigate the effect of acid phosphatase on nanoparticle stability. The resulting AFM images enabled direct nanoscale characterization of the particles, with nanoparticle sizes determined from the measured particle heights.

The use of a NanoWorld AFM probe in tapping mode provided a suitable approach for imaging these nanoscale polymer-based structures while limiting the interaction between the AFM probe and the deposited nanoparticles. The NanoWorld PointProbe® NCSTR-50 AFM probe therefore played an important role in confirming the morphology and dimensions of the lignin-TPP nanofertilizers.

This work highlights how NanoWorld AFM probes can support nanoscale characterization of responsive polymer nanoparticles and advanced agricultural materials. By combining AFM-based morphological analysis with biochemical response testing and plant experiments, the authors demonstrate a promising approach toward nanofertilizers capable of delivering phosphorus in a plant-growth-synchronized manner.

The study also illustrates the broader potential of nanoscale characterization in the development of responsive agricultural materials, where nanoparticle size, morphology, stability, and stimulus-dependent behavior can all influence the performance of the final delivery system.

Figure 6.AFM images of cross-linked lignin/TPP nanoparticles after A) 0 h, B) 24 h, C) 48 h, and D) 72 h of incubation with acid phosphatase (10 mU/mL). — Figure 6.
AFM images of cross-linked lignin/TPP nanoparticles after A) 0 h, B) 24 h, C) 48 h, and D) 72 h of incubation with acid phosphatase (10 mU/mL).

Full citation:
Boarino, A.; Carrara, N.; Clua, J.; Zahnd, N.; Poirier, Y.; Klok, H.-A.
Plant-Growth Synchronized, Acid Phosphatase-Responsive Lignin-Based Controlled Release Phosphorus Nanofertilizers.
Biomacromolecules 2026, 27, 5, 3176–3187.
https://doi.org/10.1021/acs.biomac.5c02594

Creative Commons license: CC BY 4.0

NanoWorld – A New Look for Our Product Labels

Starting August 1, 2026, NanoWorld will begin introducing updated designs for many of our product labels.

During the transition period, you may receive products with either the current or the new label design shown below. The label version simply reflects the ongoing implementation of our new labeling system and is not related to the product itself or its date of manufacture.

The updated labels continue to display the nominal resonant frequency and nominal force constant of each AFM probe and now include a QR code linking directly to the corresponding product page. This provides convenient access to the complete set of available AFM probe specifications and related technical product information.

Products with multiple cantilevers (such as the Pyrex-Nitride Series) and customized products will continue to use their current labels, reflecting their specific labeling requirements.

While the labels are changing, the AFM probes themselves remain the same. We hope this update makes it even more convenient to access product information when you need it.

Current NanoWorld AFM probe product label showing the nominal resonant frequency and nominal force constant. — Current product label for NanoWorld AFM probes.

Updated product label on NanoWorld ESD-safe AFM probe packaging featuring a QR code linking to product specifications.