Home > Press > Super-strong magnetic supercrystals can assemble themselves
Tools of the trade: a three-necked flask (left) to cook up the solution that makes nanocubes, and a complex piping system that condenses the solution if it evaporates and controls the gas flow during the reaction. CREDIT Photo: Nancy Bazilchuk/NTNU |
Abstract:
Verner Håkonsen works with cubes so tiny that nearly 5 billion of them could fit on a pinhead.
He cooks up the cubes in the Norwegian University of Science and Technology's (NTNU) NanoLab, in a weird-looking glass flask with three necks on the top using a mixture of chemicals and special soap.
And when he exposes these invisible cubes to a magnetic field, they perform a magical feat: they assemble themselves into whatever shape he wants.
"It's like building a house, except you don't have to build it," he says. The magnetic force along with other forces cause "the house to build itself -- all the building blocks assemble themselves perfectly under the right conditions."
Although researchers have previously been able to cause nanoparticles to assemble themselves in different ways, Håkonsen and his colleagues are the first to show how important magnetism can be with respect to the mechanical properties of certain nanoparticle structures.
The researchers called their tiny nanocube creations superstructures or supercrystals because the nanocubes are organized in an ordered pattern, kind of like atoms in a crystal. "Supercrystals are particularly interesting because they show enhanced properties compared with a single nanoparticle or with a bulk material," Håkonsen said.
The big finding is that when magnetic cubes are self-assembled in a supercrystal -- in shapes like lines or rods or helices, for example -- the cohesive energy between the particles in the supercrystal can increase by as much 45 per cent because of the magnetic interactions between the cubes.
"That means the energy holding the whole thing together increases up to 45 per cent," he said.
The strength of the supercrystals in combination with their enhanced magnetic properties will be key to developing future uses, which could span everything from applications for the automotive industry to information technology. Håkonsen's research has just been published in the journal Advanced Functional Materials.
When things get tiny, physics gets weird
One central tenet of nanoparticle research is that the smaller the particles, the stranger their behaviour.
That's because as the size shrinks, the surface area of the particle represents a much greater percentage of the overall volume of the structure than in particles that are not nano-sized.
"As a result, the smaller the nanoparticles are, the more unstable they can be," Håkonsen said. This is what is known as the "size effect" in nanoscience, and is one of the fundamental aspects of nanotechnology as things get smaller than 100 nm.
"You can even have particles that spontaneously shift between different crystal structures, because of their small size," he explained. "The particles partly melt."
The size effect also affects other properties in small nanoparticles, like magnetic properties, where the magnetic field from the particle can start to jump around by itself in different directions.
Size still matters
In other words, even though magnetism could make the researchers' self-assembled nanostructures strong, the size effect still played a role. When the supercrystals were super small, the structures were weaker than their larger counterparts.
"What that means is that you have a size effect when it comes to mechanical stability also in supercrystals - a "super-size effect" - but it also suggests that there are size effects for other supercrystal properties," Håkonsen said. "What is also remarkable is that this super-size effect goes beyond the nanoscale, and up towards the microscale."
Rather than posing a problem, however, in this case knowing that the size effect will affect the supercrystals could allow researchers to control -- or tune-- how the structures behave through a variety of different factors.
"This could open up a new field, size-controlled tuning," Håkonsen said. "It could be possible to control the features of supercrystals, not just by how particles themselves are made, but by the shape and size of the supercrystal and the number of particles in it."
Magnetite cubes
Håkonsen's research at the NTNU Nanomechanical Lab relies on nanocubes that he himself manufactures from magnetite, which is why they self-assemble in response to a magnetic field.
Essentially, he makes a molecule that he then heats up in a solvent containing a soap-like substance called a surfactant. The surfactant prevents the nanocubes from getting too big and can also control the shape of the nanoparticle. In this way, Håkonsen and his team can make cubes and spheres, among other shapes.
Håkonsen's collaborators are drawn from across disciplines, including physicists, mechanical and materials scientists and computational experts, and come from the University of Sydney and UCLM (Universidad de Castilla-La Mancha) in addition to NTNU. The researchers chose to use cubes for their study because there has been less research on cubes than spheres, and cubes are also the most likely to provide the strongest structure, he said.
"This is fundamental research. Our motivation has been to investigate how magnetism affects mechanical properties in supercrystals," he said. "It's important because we have all these potential applications, but to realize them, we also need mechanically stable supercrystals."
###
Håkonsen said he and his collaborators are continuing their research to learn more about how magnetism can be used to tune the mechanical properties in magnetic supercrystals.
####
For more information, please click here
Contacts:
Verner Håkonsen
47-735-94543
Copyright © Norwegian University of Science and Technology
If you have a comment, please Contact us.Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Related Links |
Related News Press |
Magnetism/Magnons
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
Physics
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
News and information
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Possible Futures
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
With VECSELs towards the quantum internet Fraunhofer: IAF achieves record output power with VECSEL for quantum frequency converters April 5th, 2024
Self Assembly
Liquid crystal templated chiral nanomaterials October 14th, 2022
Nanoclusters self-organize into centimeter-scale hierarchical assemblies April 22nd, 2022
Atom by atom: building precise smaller nanoparticles with templates March 4th, 2022
Nanostructures get complex with electron equivalents: Nanoparticles of two different sizes break away from symmetrical designs January 14th, 2022
Discoveries
Chemical reactions can scramble quantum information as well as black holes April 5th, 2024
New micromaterial releases nanoparticles that selectively destroy cancer cells April 5th, 2024
Utilizing palladium for addressing contact issues of buried oxide thin film transistors April 5th, 2024
Announcements
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Automotive/Transportation
Researchers’ approach may protect quantum computers from attacks March 8th, 2024
Tests find no free-standing nanotubes released from tire tread wear September 8th, 2023
Research partnerships
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Researchers’ approach may protect quantum computers from attacks March 8th, 2024
'Sudden death' of quantum fluctuations defies current theories of superconductivity: Study challenges the conventional wisdom of superconducting quantum transitions January 12th, 2024
The latest news from around the world, FREE | ||
Premium Products | ||
Only the news you want to read!
Learn More |
||
Full-service, expert consulting
Learn More |
||