People usually associate holograms with futuristic 3D display technologies, but in reality, holographic technologies are now being used to help study materials at the atomic level. X-rays, a high energy form of light, are often used to study atomic structure.
However, X-rays are only sensitive to the number of electrons associated with an atom. This limits the use of X-rays for studying materials made up of lighter elements. Neutron measurements can often fill in the gaps in structures when X-ray measurements fail, but neutron beams are harder to make and have lower intensities than X-ray beams, which limits their versatility.
Nearest Ca2+ images are split into two parts due to the extra positive charge by Eu3+. The interstitial F- image is observed between Ca2+ images. The additional F- is needed for the compensation of the excessive charge. Dashed circles indicate original positions of Ca atoms without doping Eu.
Now, a collaboration among Japanese researchers working at national particle accelerator facilities across Japan has developed a new multiple-wavelength neutron holography technique that can give insights into previously unknown structures.
They demonstrated a new neutron holographic method using a Eu-doped CaF2 single crystal and obtained clear three-dimensional atomic images around trivalent Eu substituted divalent Ca, revealing never-before-seen intensity features of the local structure that allows it to maintain charge neutrality.
"We knew that neutron holography might be able to tell us more about the structure of a europium-doped calcium fluoride crystal," says lead author Kouichi Hayashi.
"Europium ions add extra positive charge to the crystal structure, and our neutron holograms showed how fluorine atoms arranged in the lattice to balance this excess charge. These kinds of structural problems are often encountered by materials scientists developing new electronic materials, and our method offers an exciting new tool for these researchers."
The new holographic method works by firing neutrons with controlled speed at a sample, which in this case is the europium-doped calcium fluoride crystals. Neutrons are normally thought of as particles, but also have wave-like properties similar to light, depending on their speed.
When the neutrons hit europium atoms, gamma rays are produced in a pattern controlled by the local structure. The gamma ray patterns, or holograms, measured from neutrons travelling at different speeds are combined to produce a three-dimensional representation of the europium atoms in the crystal.
Hayashi says, "Neutron sources are less intense than X-ray sources, but it is essential that we work around this issue to develop more effective methods for exploring structures with light elements. Our work here represents a step towards a full toolbox of commentary X-ray and neutron techniques for materials research."
Kuniaki Shiraki | EurekAlert!
Watching atoms move in hybrid perovskite crystals reveals clues to improving solar cells
22.11.2017 | University of California - San Diego
Fine felted nanotubes: CAU research team develops new composite material made of carbon nanotubes
22.11.2017 | Christian-Albrechts-Universität zu Kiel
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
23.11.2017 | Information Technology
23.11.2017 | Physics and Astronomy
23.11.2017 | Life Sciences