Pulsed Field Science Highlights
In-House Fabrication of Outsert Coil 1 for the 100T Pulsed Magnet
Pulsed magnets are designed to operate near their structural limits to be able to generate extremely high magnetic fields. The coils have a limited life expectancy and thus need to be replaced on occasion. Fabrication of these large coils are now being done at the MagLab where advanced nondestructive examinations can be performed. Because of more rigorous quality controls and improvements in high-strength conductors and reinforcement materials, the lifetime of these coils can be extended.
Destruction of Weyl nodes and a new state in tantalum arsenide above 80 teslas
Weyl metals such as tantalum arsenide (TaAs) are predicted to have novel properties arising from a chirality of their electron spins. Scientists induced an imbalance between the left- and right-handed spin states, resulting in a topologically protected current. This was the first time this phenomenon, known as the chiral anomaly, has been observed.
Phase diagram of URu2–xFexSi2 in high magnetic fields
Scientists used high magnetic fields and low temperatures to study crystals of URu2–xFexSi2. Using these conditions, they explored an intriguing state of matter called the "hidden order phase" that exhibits emergent behavior. Emergent behavior occurs when the whole is greater than the sum of its parts, meaning the whole has exciting properties that its parts do not possess; it is an important concept in philosophy, the brain and theories of life. This data provide strict constraints on theories of emergent behavior.
Exciton states in a new monolayer semiconductor
Analogous to the unique spectral fingerprint of any atom or molecule, researchers have measured the spectrum of optical excitations in monolayer tungsten diselenide (WSe2), which is a member of a new family of ultrathin semiconductors that are just one atomic layer thick.
New magnetic topological semimetal has energy-saving potential
Researchers discover that Sr1-yMn1-zSb2 (y,z < 0.1) is a so-called Weyl material that holds great promise for building devices that require far less power.
Selective mass enhancement close to a quantum critical point
This finding sheds light on the role of quasiparticle mass enhancement near a quantum critical point in one of the leading families of high-temperature superconductors.
Connection between superconductivity and insulator-metal transition
The finding in fullerides opens a new way of exploring the role electron interactions play in high-temperature superconductivity
Tunable, 2D semiconductors could be tomorrow's nano-sensors
Scientists discovered how to tune the optical properties of atomically-thin semiconductors, which will aid the design of future microscopic light sensors.
New technique for identifying Weyl materials
The work gives physicists a new tool for exploring and understanding a class of materials that could lead to faster electronics.
Upper critical field of iron-based superconductor discovered
Scientists discovered how strong of a magnetic field was necessary to suppress superconductivity in a thin film of iron-selenium.
New properties revealed in atomically-thin semiconductors
Scientists begin to fill in the blanks on transition metal dichalcogenides.
Colossal magnetoelectric coupling probed to 90 teslas
Ni3TeO6 provides a new approach to coupling magnetism to ferroelectricity with a record large response. We measured this material's magnetic and electric properties across an extended range of temperature and magnetic field and compared with theoretical calculations to extract a model that describes the underlying reason for a large magnetoelectric coupling. High magnetic fields were key to establishing the magnetic Hamiltonian. This work is motivating the discovery of further 3d-4d oxide materials with large magnetoelectric couplings.
Quasiparticle mass enhancement approaching optimal doping in a high-Tc superconductor
Using magnetic fields of over 90 T, the effective mass in the high-Tc superconductor YBa2Cu3O6+x was shown to be strongly enhanced as the material is doped toward optimal Tc.
Atomic pantograph tunes magnetic ground state in a solid
A novel approach combining pulsed field optical FBG strain measurements in world-class magnets, with Density Functional based calculations to pinpoint the peculiar nanopantograph mechanism behind the magnetoelastic coupling, allows researchers to conclude that magnetic field and pressure are alternative ways to tune the quantum properties of the Shastry-Sutherland compound SrCu2(BO3)2
Transport in the quantum critical regime of the iron arsenide superconductor BaFe2(As1-x Px)2
High magnetic fields reveal the electronic interactions underlying high-temperature superconductivity in the iron pnictides. This research unifies the superconducting phase diagram of the pnictides with those of other quantum critical, high-temperature superconductors, such at the cuprates.
Normal State Electronic Structure in Underdoped High-Tc Cuprates
Comprehensive angle-resolved quantum oscillation measurements on YBa2Cu3O6+x in magnetic fields approaching 100 tesla are used to address longstanding problem of the normal state electronic of underdoped high temperature superconducting cuprates. The symmetry of the Fermi surface points uniquely to its reconstruction by biaxial ordering of the charge and bond degrees of freedom.
Interplay between Frustration and Spin-Orbit Coupling in Vanadates
The high-magnetic field phase diagram to 65 Tesla of the MV2O4 family (M = Cd, Mg) reveals new multiferroic phase transitions that point to an unusual interplay between spin-orbit interactions and frustrated magnetism.
Bounding the Pseudogap in Cuprate High-TC Superconductors
Scientists of the NHMFL-PFF have employed Resonant Ultrasound Spectroscopy to reveal a thermodynamic signature of the “Pseudo-Gap” within and beyond the superconducting phase boundary of YBCO. This experiment provides thermodynamic evidence that the pseudo gap is connected to the superconducting ground state in the cuprate materials.
Magnetic Field-Induced Delocalized to Localized Transformation in GaAs:N
Using optical spectroscopy and the MagLab’s unique 60 tesla long-pulse magnet in Los Alamos, scientists have shown how nitrogen dopant atoms in gallium arsenide (GaAs) can form extended “supercluster” states or can break up into localized nitrogen clusters. Nitrogen-doped GaAs (GaAs1-xNx) is a semiconductor alloy with potential applications for a wide range of energy-related applications such as photovoltaics.
Magnetic Structure and Magneto–electric Coupling in Multiferroics
Multiferroics — “Spintronics without heat” — coupled ferromagnetism and ferroelectricity can provide a new class of functional materials for needed applications including magnetic sensing, data storage and manipulation, high–frequency and high–power electronics, and energy savings.
