Researchers used x-ray photoemission spectroscopy (XPS) at beamline 4-ID-C to show that electrons that are spin-polarized by traversing chiral DNA can lead to chiral selective chemistry. This is manifested in an imbalance in the production of L and R enantiometers of model chiral compounds adsorbed into a self assembled monoloayer of DNA on a gold substrate. The results could explain the chiral preference in pre-biological molecules on the early Earth.
Researchers used single crystal XMCD measurements at beamlines 4-ID-C and 4-ID-D to show presence of itinerant ferromagnetism (Tc ~ 100 K) in the As 4p band of K-doped BaMn2As2 which is not associated with an underlying collinear AFM order of the Mn sublattice. The proximity of magnetic and superconducting phases in these materials provided motivation for these studies.
Researchers used XAS/XMCD measurements at 4-ID-C to probe the interface between a topological insulator and a magnetic materials with an eye at enabling advanced electronic devices including quantum computing.
Tiny, disordered particles of magnesium chromium oxide may hold the key to new magnesium battery energy storage technology, which could possess increased capacity compared to conventional lithium-ion batteries, find researchers who studied the material utilizing ultra-bright x-ray beams from the U.S. Department of Energy’s Advanced Photon Source.
4-ID-C, 10-BM-A,B, 11-ID-B
The recent application of x-ray magnetic circular dichroism spectroscopy at the U.S. Department of Energy’s Advanced Photon Source has provided an answer to a hypothesis first proposed in 2014 regarding the biological cofactor that enables the conversion of nitrogen to bioavailable ammonia.
The revolutionary tech discoveries of the next few decades, the ones that will change daily life, may come from new materials so small they make nanomaterials look like lumpy behemoths.
Researchers used XAS/XMCD measurements at beamline 4-ID-D to probe the spin and orbital moments, as well as spin-orbit coupling, in 5f states of Pu in ferromagnetic PuSb. While Pu 5f electrons are usually neither localized nor delocalized, the six 5f electrons in PuSb were found to be localized, the shape of the Pu M-edge XMCD spectra a proxy to the degree of localization.
Researchers used XAS (4-ID-D) and resonant XRD (6-ID-B) to study the role of electron-lattice coupling in the metal-insulator transition (MIT) of rare-earth nickelates by controlling lattice distortions via strain manipulation in epitaxial films. Manipulation of electrical conductivity may lead to novel electronic sensors and devices.
Researchers used resonant XRD (6-ID-B) and XAS (4-ID-D) to probe emergence of a “Polar metal” at the strained interface of an oxide heterostructure in an attempt to accelerate discovery of multifunctional materials with ability to perform simultaneous electrical, magnetic and optical functions.
Researchers used XRD (6-ID-B) and XAS/XMCD (4-ID-D) techniques to probe the effects of dimensional confinement in manganite/iridate superlattices with an eye at enabling all-oxide spintronics
Single crystal magnetic diffraction measurements at 4-ID-D were used to investigate the magnetic characteristics of a helical spin-order phase preceding a recently discovered pressure-induced superconducting phase in manganese phosphide (MnP).
Layer by layer, University of Tennessee, Knoxville physicists are exploring the frontiers of tuning material properties down to the atomic level. Experimenting with the stacking pattern of superlattices at the U.S. Department of Energy’s Advanced Photon Source, the UT researchers and their colleagues investigated inter- and intra-layer dynamics to learn more about magnetism on the nanoscale, with potential connections to high-temperature superconductivity and spintronics.
Actinides are a series of chemical elements that form the basis of nuclear fission technology, finding applications in strategic areas such as power generation, space exploration, diagnostics and medical treatments, and also in some special glass. Thorium and Uranium are the most abundant actinides in the Earth's crust. A deeper understanding of the properties of uranium and other actinides is necessary not only for their more efficient use in existing applications but also for proposing new applications. Several open questions remain; progress in this area is usually limited in part by the difficulty in handling these materials safely.
A team of researchers used a combination of high-resolution structural imaging, magnetic domain imaging, and dichroic spectroscopy on three separate x-ray beamlines at the U.S. Department of Energy’s Advanced Photon Source to shed light on coupled structural and magnetic phase transitions. Through this combination of three individually powerful x-ray techniques, the team was able to provide added insights into the phase transition process and the nature of the coupling between the magnetic and structural order.
Two-dimensional (2-D) crystalline films often exhibit interesting physical characteristics, such as unusual magnetic or electric properties. By layering together distinct crystalline thin films, a so-called “superlattice” is formed. Due to their close proximity, the distinct layers of a superlattice may significantly affect the properties of other layers. In this research, single 2-D layers of strontium iridium oxide were sandwiched between either one, two, or three layers of strontium titanium oxide to form three distinct superlattices. Researchers then used x-ray scattering at the U.S. Department of Energy’s Advanced Photon Source to probe the magnetic structure of each superlattice.
A new material created by Oregon State University researchers and characterized with help from the U.S. Department of Energy’s Advanced Photon Source and Oak Ridge National Laboratory is a key step toward the next generation of supercomputers. Those “quantum computers” will be able to solve problems well beyond the reach of existing computers while working much faster and consuming vastly less energy.
Sometimes a good theory just needs the right materials to make it work. That’s the case with recent findings by University of Tennessee, Knoxville’s physicists and their colleagues, who designed a two-dimensional magnetic system that points to the possibility of devices with increased security and efficiency, using only a small amount of energy. The researchers studied the hidden physical properties of the material by utilizing high-brightness x-rays from the U.S. Department of Energy’s Advanced Photon Source, an Office of Science user facility at Argonne National Laboratory.
4-ID-D, 6-ID-B,C, 33-BM-C
Jarosite, a hydrous sulfate mineral exhibiting unusual magnetic behavior, has intrigued scientists in a range of fields from planetary science to inorganic chemistry. Interactions between iron ions in the material’s lattice structure cause instances of magnetic frustration, which should lead the material to be magnetically disordered. So then, why does jarosite display overall magnetic order under certain conditions? Previous attempts to unravel the mystery of jarosite’s magnetism resulted in contradictory data. Researchers now understand that past studies lacked the technology necessary to account for the material’s myriad magnetic interactions. In this study, researchers working at the U.S. Department of Energy’s Advanced Photon Source subjected samples of jarosite to extreme pressures in order to systematically vary local coordination environments throughout the material, then observed how these changes affected the material’s magnetic ordering behavior. These findings ultimately unveiled the mechanism for jarosite’s three-dimensional magnetic ordering and revealed a great deal about the nature of geometric magnetic frustration. Moreover, this study serves as a blueprint for how chemists can use pressure to conduct chemically pure magnetostructural correlation studies. By bringing high-pressure techniques to the attention of the chemical community, even the most perplexing magnetostructural mechanisms can be unraveled.
4-ID-D, 13-BM-C, 16-ID-B
Researchers used resonant magnetic scattering measurements at beamline 6-ID-B to probe magnetic ordering in Na2IrO3, a material where anisotropic exchange (Kitaev) interactions dominate over isotropic (Heisenberg) exchange interactions. Spin-orbit coupling in heavy Ir atoms is at the root of the bond-directional exchange interactions. In the absence of competing Heisenberg interactions, a quantum spin liquid ground state can emerge when the geometrical arrangement of Ir magnetic moments leads to frustration.
Researchers used x-ray resonant scattering measurements at 6-ID-B to probe the collapse of magnetic ordering in Mott insulator iridate Sr3Ir2O7 as electrons are doped with La doping at the Sr site. The first-order collapse of magnetic order coincided with emergence of a metallic state.
Sometimes a little frustration and disorder can be a good thing, at least in the quest for the elusive and exotic state of matter known as a quantum spin liquid (QSL). In such systems, the electrons are strongly “entangled,” a quantum phenomenon that is the basis of quantum computing but has proven extremely difficult to recreate except under tightly controlled laboratory environments. But QSLs naturally form such states, arising from their strong interactions (or correlations) that also serve to protect their entanglement from environmental influences. One class of these systems is the Kitaev quantum spin liquid, which takes advantage of anisotropic magnetic interactions on a honeycomb lattice.
A multi-national team of researchers using the U.S. Department of Energy’s APS probed the magnetic and crystalline properties of two superlattices and described magnetic tunability that should prove applicable to numerous other superlattice systems, which may be adapted for improved electronic devices.
6-ID-B,C, 27-ID-B, 33-BM-C
Researchers used high energy XRD at beamline 6-ID-D, coupled with aerodynamic levitation, to study the liquid/solid transition of high-entropy alloys with an eye at enabling new generation materials with enhanced mechanical properties.
Researchers used high energy diffraction measurements of aerodynamically-levitated, glass-forming liquids at 6-ID-D to investigate the liquid and glass structures of Sodium Borate. The goal is to discover glasses that are more functional and test models of glass formation.
The behavior of iron at high temperatures and pressures plays an important part in our understanding of Earth's interior. Scientists must quantify how iron's physical and chemical characteristics are both affected by and affect the environment within Earth's mantle and core to make sense of the reactions which molten, subsurface magmas undergo. Researchers using high-brightness x-rays at the U.S. Department of Energy’s Advanced Photon Source at Argonne monitored the behavior of a model iron silicate melt to investigate how its structure and oxidation state change as a function of the amount of oxygen present. These new results — using melts based on fayalite (Fe2SiO4), the iron-rich end-member of the olivine solid-solution series — reveal contrasting behavior between this melt and more silicic magmas, including basaltic melts.
By combining x-ray diffraction data from the U.S. Department of Energy’s APS with other structural data and computer modeling, researchers uncovered the secrets behind how a glass can act like a crystal.