News from the NNI Community - Research Advances Funded by Agencies Participating in the NNI

Researchers from the University of Virginia, the University of California-Berkeley, the University of Florida, the University of Tennessee-Knoxville, the University of Michigan, and the U.S. Department of Energy’s Sandia National Laboratories and Center for Integrated Nanotechnologies have developed an innovative technique to better determine the nanoscale effects of radiation on materials. Using advanced time-series imaging techniques with a transmission electron microscope, the team compiled more than 1,000 images capturing more than 250,000 defects formed during ion irradiation. The study revealed that defects in copper and gold exhibit different behaviors compared to those in palladium. This distinction underscores the need for specialized analytical models to accurately study these materials under radiation.

A difficult-to-describe nanoscale object called a magnetic skyrmion – which can be thought of as spinning circles of magnetism – might one day yield new microelectronic devices that can do more while consuming less power. Researchers from the Department of Energy's (DOE) Lawrence Berkeley National Laboratory (Berkeley Lab), Paul Scherrer Institute in Villigen, Switzerland, and Western Digital Corporation (San Jose, CA) have now made three-dimensional (3D) X-ray images of magnetic skyrmions. "Our results provide a foundation for nanoscale metrology for spintronics devices," said Peter Fischer, the scientist who led this study. The research was conducted in part at the Molecular Foundry, a DOE Office of Science user facility at Berkeley Lab.

Researchers from New York University, the U.S. Department of Energy’s Brookhaven National Laboratory, the Korea Advanced Institute of Science and Technology, and the National Institute for Materials Science in Tsukuba, Japan, have pioneered a new technique to identify and characterize atomic-scale defects in a two-dimensional (2D) material called hexagonal boron nitride. The team was able to detect the presence of individual carbon atoms replacing boron atoms in this material. "In this project, we essentially created a stethoscope for 2D materials," said Davood Shahrjerdi, one of the researchers involved in this study. "By analyzing the tiny and rhythmic fluctuations in electrical current, we can 'perceive' the behavior of single atomic defects."

Researchers from the U.S. Department of Energy’s Argonne National Laboratory and Lawrence Berkeley National Laboratory; Rice University; and Penn State University have revealed an adaptive response with a ferroelectric device, which responds to light pulses in a way that resembles the plasticity of neural networks. This behavior could find application in energy-efficient microelectronics. The material is laden with networked islands or domains that are nanometers in size and can rearrange themselves in response to light pulses. 

Researchers from Johns Hopkins University and the National Institute of Standards and Technology have developed a new blood test that diagnoses heart attacks in minutes rather than hours. The heart of the invention is a tiny chip with a groundbreaking nanostructured surface on which blood is tested. The chip's "metasurface" enhances electric and magnetic signals during Raman spectroscopy analysis, making heart attack biomarkers visible in seconds. The tool is sensitive enough to flag heart attack biomarkers that might not be detected with current tests. "We're talking about speed, we're talking about accuracy, and we're talking of the ability to perform measurements outside of a hospital," said Ishan Barman, one of the scientists involved in this study.

A nanocrystalline material is made up of many tiny crystals, but as they grow, the nanocrystalline material can weaken. Researchers from Lehigh University, Johns Hopkins University, George Mason University, the University of Tennessee, Knoxville, and the U.S. Department of Energy’s Lawrence Berkeley National Laboratory and Sandia National Laboratories have discovered that the key to maintaining the stability of nanocrystalline materials at high temperatures lies in triple junctions – corners where three of these nanocrystals meet. What the scientists found is that when certain atoms are added to form an alloy, they prefer to occupy sites at these triple junctions, which prevents the nanocrystalline material from losing its strength over time. 

Scientists from the University of Massachusetts Amherst; The Connecticut Agricultural Experiment Station in New Haven, CT; the University of Bern in Switzerland; the University of Auckland in New Zealand; Guangdong University of Technology in China; Central South University of Forestry and Technology in Changsha, China; the Chinese Academy of Forestry in Hangzhou, China; and Beijing Forestry University in China have shown that nutrients on the nanometer scale can not only blunt some of the worst effects of heavy metal and metalloid contamination, but increase crop yields and nutrient content. The scientists found that nanomaterials are more effective than conventional fertilizers at mitigating the harmful effects of polluted soil (by 38.3%), can enhance crop yields (by 22.8%) and the nutritional value of those crops (by 30%), as well as combat plant stress (by 21.6%) due to metal and metalloid pollution. 

Researchers from North Carolina State University and the U.S. Department of Energy’s Brookhaven National Laboratory have developed and demonstrated a technique that allows them to engineer a class of materials called layered hybrid perovskites down to the atomic level, which dictates precisely how the materials convert electrical charge into light. Layered hybrid perovskites can be laid down as thin films consisting of multiple sheets of perovskite and organic spacer layers. These materials are desirable because they can efficiently convert electrical charge into light. The researchers discovered that individual sheets of the perovskite material, called nanoplatelets, form on the surface of the solution that is used to create the layered hybrid perovskites, and these nanoplatelets serve as templates for layered materials that form under them. 

Researchers at the Massachusetts Institute of Technology and Friedrich-Alexander University of Erlangen–Nuremberg in Germany have developed novel magnetic nanodiscs that could provide a less invasive way of stimulating parts of the brain, paving the way for stimulation therapies without implants or genetic modification. Deep brain stimulation (DBS) is a common clinical procedure that uses electrodes implanted in the target brain regions to treat symptoms of neurological and psychiatric conditions. Despite its efficacy, the surgical difficulty and clinical complications associated with DBS limit the number of cases where such an invasive procedure is warranted. The new nanodiscs could provide a more benign way of achieving the same results.

Scientists from Penn State and the National Aeronautics and Space Administration’s Goddard Space Flight Center have developed an electronic tongue that can identify differences in similar liquids, such as milk with varying water content; different soda types and coffee blends; and signs of spoilage in fruit juices. The researchers also found that results were more accurate when artificial intelligence (AI) used its own assessment parameters to interpret the data generated by the electronic tongue. The tongue contains a graphene-based ion-sensitive field-effect transistor – a conductive device that can detect chemical ions – that is linked to an artificial neural network trained on various datasets.