In a huge breakthrough, UCLA scientists and partners have succeeded in making a three-dimensional reconstruction of more than 23,000 atoms packed in a tiny nanoparticle of iron and platinum. The details obtained on the alloy's atomic coordinates have been deemed a great feat.

The achievement was made possible by the use of powerful electron microscopy.

Led by Peter Ercius of Lawrence Berkeley National Laboratory and Jianwei Miao of UCLA, the team examined the nanoparticle that was only 8.4 nanometers across.

Multiple images of the nanoparticle were subjected to detailed analysis using algorithms to derive a precise, three-dimensional structure of the particle.

"For the first time, we can see individual atoms and chemical composition in three dimensions. Everything we look at, it's new," Miao said.

The structure offered researchers a new insight in measuring the chemical order of the material at a single-atom level.

The study has been published in the journal Nature.

Particle Analysis

The team studied the alloy with an aim to explore it for advanced use in creating new generation magnetic storage and media applications.

The 3D reconstruction showed how atoms have been arranged in nine grains. The team found that atoms which were closer to the interiors of the grains were more in order compared with those at the surfaces. Also, the interfaces between grains, known as grain boundaries, were not seen in order.

The information from the particle's structure will now be put to use in improving the magnetic performance for making high-density, next-generation hard drives.

Thanks to the atomic electron tomography method, optimizing the particles for making stronger materials has become bright.

It is a big leap in curing the imperfections in nanomaterials at the atomic level, such as missing atoms, swapped atoms and wrongly aligned atoms. These aspects do influence properties and functions of a material.

Why Does Structure Matter?

Regarding the big question why anyone should care about the location of each little atom, Michael Farle from the University of Duisburg-Essen in Germany noted that every atom counts at a nanoscale.

By changing the positions of a few iron and platinum atoms in the nanoparticle studied, the particle's properties in terms of its response to a magnetic field can be changed drastically.

This is because the arrangement of atomic patterns is linked to a material's functions and properties. By determining the 3D structure of nanoparticles at the smallest scale, innovations can be planned.

According to Mio, the work has broadened the vistas of knowledge on the relation between structure and a material's property with the scope for new applications in physics, nanotechnology and chemistry.

For pushing the frontier further into other fields, researchers are mulling 3D mapping of more materials. An online databank for the physical sciences along the lines of protein databanks in life sciences is under consideration.

The GENeralized Fourier Iterative Reconstruction method of UCLA suits the biological segment as well, according to Mio, who also claimed that the algorithm might be of use in imaging CT scans.

The nanoparticle reconstruction adds to the achievement of UCLA team that in 2016 measured the coordinates of thousands of atoms in a tungsten needle to 19 trillionths of a meter, which is so many times smaller than a hydrogen atom.

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