Phys.org April 8, 2024 Magnetism can cause a modulation of superconducting pairing in real space in both copper-based and iron-based materials. Researchers in China reported on the discovery of a spatially varying superconducting state residing at the interface between KTaO3 and ferromagnetic EuO. Electrical transport measurements revealed different values of the critical temperature and magnetic field at which the superconductivity breaks down when current was applied along the two orthogonal in-plane directions. This anisotropy occurred in low-carrier-density samples that were characterized by strong coupling between the Ta 5d and Eu 4f electrons, whereas in high-carrier-density samples, the coupling was weakened, […]
Tag Archives: Magnetism
Magnetic avalanche triggered by quantum effects: ‘Barkhausen noise’ detected for first time
Phys.org March 28, 2024 Most macroscopic magnetic phenomena (including magnetic hysteresis) are typically understood classically. An international team of researchers (USA – Caltech, University of Colorado, University of Chicago, University of Tennessee, Canada, Japan, UK) examined the dynamics of a uniaxial rare-earth ferromagnet deep within the quantum regime, so that domain wall motion, and the associated hysteresis, was initiated by quantum nucleation, which then grew into large-scale domain wall motion, that was observable as an unusual form of Barkhausen noise. They found that the “quantum Barkhausen noise” exhibited two distinct mechanisms for domain wall movement, each of which was quantum-mechanical, […]
Nano weaving creates ‘Chinese knot’ magnetism for powerful microwave shielding
Nanowerk February 7, 2024 Harnessing tailored nanoscale magnetic materials like metal-organic frameworks for advanced applications has faced two key challenges – reliably constructing these frameworks with specific and programmable architectural arrangements and effectively characterizing these nanostructures. Researchers in China strategically dispersed magnetic Co nanoparticles into a meticulously layered nanoporous framework with the bottom and upper nanopores exhibiting a staggered arrangement. The staggered nanoporous structure intricately shapes the magnetic flux lines into a Chinese knot shape, significantly altering its magnetic characteristics. Such a transformation remarkably enhances the material’s efficacy in absorbing electromagnetic waves, covering the Ku band even at a minimal […]
Strange New Kind of Magnetism Found Lurking In Material Just Six Atoms Thick
Science Alert February 4, 2024 The existence of alternate mechanisms for magnetism that could naturally facilitate electrical control has been discussed theoretically but an experimental demonstration has not been done. An international team of researchers (Switzerland, Spain, US -University of Tennessee, Japan) investigated MoSe2/WS2 van der Waals heterostructures in the vicinity of Mott insulator states of electrons forming a frustrated triangular lattice and observed direct evidence of magnetic correlations originating from a kinetic mechanism. By directly measuring electronic magnetization they found that when the Mott state was electron-doped, the system exhibited ferromagnetic correlations in agreement with the Nagaoka mechanism… read […]
Nanoscale rust: The future of magnets?
Phys.org October 5, 2023 Multiferroics have tremendous potential to revolutionize logic and memory devices through new functionalities and energy efficiencies. To better understand and enhance their ferroic orders and couplings an international team of researchers (Canada, USA – Lawrence Berkeley National Laboratory, Argonne National Laboratory) used epsilon iron oxide (ϵ-Fe2O3) as a model system with a simplifying single magnetic ion. Using 15, 20, and 30 nm nanoparticles, they found that a modified and size-dependent Fe–O hybridization changed the spin–orbit coupling. However, the size effects disappeared in the high-temperature phase where the strongest Fe–O hybridization occurred. By manipulating hybridization, they could […]
One-unit-cell thick semiconductors with room-temperature magnetism
Nanowerk November 15, 2022 Researchers in China have developed a confined-van der Waals epitaxial approach to synthesizing air-stable semiconducting cobalt ferrite nanosheets with thickness down to one unit cell using a facile chemical vapor deposition process. They demonstrated hard magnetic behavior and magnetic domain evolution by means of vibrating sample magnetometry, magnetic force microscopy and magneto-optical Kerr effect measurements, which showed high Curie temperature above 390 K and strong dimensionality effect. According to the researchers their work provides possibilities for numerous novel applications in computing, sensing and information storage…read more. Open Access TECHNICAL ARTICLE
Physicists manipulate magnetism with light
Nanowerk January 28, 2022 The non-equilibrium driving of dressed quasiparticles offers a promising platform for realizing unconventional many-body phenomena and phases beyond thermodynamic equilibrium. An international team of researchers (USA – MIT, South Korea) achieved this in the van der Waals correlated insulator NiPS3 by photoexciting its newly discovered spin–orbit-entangled excitons that arise from Zhang-Rice states. By monitoring the time evolution of the terahertz conductivity, they observed the coexistence of itinerant carriers produced by exciton dissociation and a long-wavelength antiferromagnetic magnon that coherently processes in time. These results demonstrate the emergence of a transient metallic state that preserves long-range antiferromagnetism, […]
New data-decoding approach could lead to faster, smaller digital tech
Phys.org December 28, 2021 An international team of researchers (USA – University of Nebraska, University of Wisconsin, China) has shown that spin-independent conductance in compensated antiferromagnets and normal metals can be efficiently exploited in spintronics, provided their magnetic space group symmetry supports a non-spin-degenerate Fermi surface. Due to their momentum-dependent spin polarization, such antiferromagnets can be used as active elements in antiferromagnetic tunnel junctions (AFMTJs) and produce a giant tunneling magnetoresistance (TMR) effect. Using RuO2 as a representative compensated antiferromagnet exhibiting spin-independent conductance they designed a RuO2/TiO2/RuO2 (001) AFMTJ, where a globally spin-neutral charge current was controlled by the two […]
Magnetic ‘hedgehogs’ could store big data in a small space
Nanowerk December 17, 2021 An international team of researchers (USA- Ohio State University, Mexico) used a magnetic microscope to visualize the patterns formed in thin films of manganese germanide. The magnetism in this material follows helices, like the structure of DNA which leads to numerous patterns. The images revealed that in certain parts of the sample, the magnetism at the surface was twisted into a pattern resembling the spikes of a hedgehog, about 50 nanometers in size. The hedgehog patterns could be shifted on the surface with electric currents or inverted with magnetic fields. This foreshadows the reading and writing […]
Ultrafast magnetism: Heating magnets, freezing time
Phys.org October 18, 2021 Magnetic solids can be demagnetized quickly with a short laser pulse. However, the microscopic mechanisms of ultrafast demagnetization remain unclear. Researchers in Germany have developed a method to quantify the temperature-dependent electron–phonon scattering rate in gadolinium measuring independently the electron-phonon scattering rate for the 5d and the 4f electrons. They deduced the temperature dependence of scattering for the 5d electrons, while no effect on the phonon population is observed for the 4f electrons. The results suggest that the ultrafast magnetization dynamics in Gd is triggered by the spin-flip in the 5d electrons, found evidence of the […]