Intricate magnetic configuration of 3D nanoscale gyroid networks revealed

April 30, 2020

A multinational team of researchers from Tohoku University and institutions in the UK, Germany and Switzerland has revealed the magnetic states of nanoscale gyroids, 3D chiral network-like nanostructures. The findings add a new candidate system for research into unconventional information processing and emergent phenomena relevant to spintronics.

Arrays of interacting nanostructures offer the ability to realize unprecedented material properties, as interactions can give rise to new, "emergent" phenomena. In magnetism, such emergent phenomena have so far only been demonstrated in 2D, in artificial spin ices and magnonic crystals. However, progress towards realizing magnetic "metamaterials", which could form the basis of advanced spintronic devices by displaying emergent effects in 3D, has been hampered by two obstacles. The first is the need to fabricate complex 3D building blocks at dimensions smaller than 100 nm (comparable to intrinsic magnetic lengthscales) and the second is the challenge of visualizing their magnetic configurations.

The research team therefore decided to study nanoscale magnetic gyroids, 3D networks composed of 3 connected vertices defined by triads of curved nanowire-like struts (Figure 1). Gyroids have attracted much interest, as despite their complexity they can self-assemble from a carefully formulated combination of polymers, which can be used as a 3D mold or template to form free-standing nanostructures (Figure 2). As the struts connect to form spirals, gyroids have a "handedness" or chirality, and their shape makes magnetic gyroids ideal systems to test predictions of new magnetic properties emerging from curvature. Measurements of the optical properties of gyroids even showed that gyroids can have topological properties, which along with chiral effects are currently the subject of intense study to develop new classes of spintronic devices. However, the magnetic states which might exist in gyroids had not yet been established, leading to the present study.

The researchers produced Ni75Fe25 single-gyroid and double-gyroid (formed from a mirror-image pair of single-gyroids) nanostructures with 11 nm diameter struts and a 42 nm unit cell, via block co-polymer templating and electrodeposition. These dimensions are comparable to domain wall widths and spin wave wavelengths in Ni-Fe. They then imaged the gyroid nanoparticles with off-axis electron holography, which could map the magnetization and stray magnetic field patterns in and around the gyroids' struts with nanometer spatial resolution. Analysis of the patterns with the aid of finite-element micromagnetic simulations revealed a very intricate magnetic state which is overall ferromagnetic but without a unique equilibrium configuration (Figure 3), implying that a magnetic gyroid can adopt a large number of stable states.

"These findings establish magnetic gyroids as a candidate of interest for applications such as reservoir computing and spin-wave logic," said lead author Justin Llandro." The research takes an exciting first step towards 3D nanoscale magnetic metamaterials which can be used to uncover new emergent effects and advance both fundamental and applied spintronics research."
-end-


Tohoku University

Related Nanostructures Articles from Brightsurf:

Unlocking PNA's superpowers for self-assembling nanostructures
Researchers at Carnegie Mellon University have developed a method for self-assembling nanostructures with gamma-modified peptide nucleic acid, a synthetic mimic of DNA.

Machine learning enhances light-matter interactions in dielectric nanostructures
The discovery has promising possibilities for the development of a wide range of photonic devices and applications including those involved in optical sensing, optoacoustic vibrations, and narrowband filtering.

Electron correlations in carbon nanostructures
Graphene nanoribbons are only a few carbon atoms wide and have different electrical properties depending on their shape and width.

Paving a way to achieve unexplored semiconductor nanostructures
A research team of Ehime University paved a way to achieve unexplored III-V semiconductor nanostructures.

Nanostructures help to reduce the adhesion of bacteria
Scientists has shown how bacteria adhere to rough surfaces at the microscopic level.

Diamonds are forever: New foundation for nanostructures
Researchers at the Okinawa Institute of Science and Technology Graduate University (OIST) have fabricated a novel glass and synthetic diamond foundation that can be used to create miniscule micro -- and nanostructures.

How do atoms vibrate in graphene nanostructures?
Researchers from the University of Vienna, the Advanced Institute of Science and Technology in Japan, the company JEOL and La Sapienza University in Rome have developed a method capable to measure all phonons existing in a nanostructured material.

Heterophase nanostructures contributing to efficient catalysis
In the research on phase engineering of noble metal nanomaterials, amorphous/crystalline heterophase nanostructures have exhibited some intriguing properties.

Dresden physicists use nanostructures to free photons for highly efficient white OLEDs
Thanks to intensive research in the past three decades, organic light-emitting diodes (OLEDs) have been steadily conquering the electronics market -- from OLED mobile phone displays to roll-out television screens, the list of applications is long.

Self-healing DNA nanostructures
DNA assembled into nanostructures such as tubes and origami-inspired shapes could someday find applications ranging from DNA computers to nanomedicine.

Read More: Nanostructures News and Nanostructures Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.