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 […]
Tag Archives: Magnetism
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 […]
‘Magnetic graphene’ forms a new kind of magnetism
EurekAlert February 8, 2021 An international team of researchers ( UK, Uzbekistan, Russia, France, USA – Oak Ridge National Laboratory, Vietnam, South Korea, Czech Republic) was able to control the conductivity and magnetism of iron thiophosphate (FePS3) which undergoes a transition from an insulator to a metal when compressed. Using new techniques to measure the magnetic structure up to record-breaking high pressures, they found that magnetism survives, but gets modified into new forms, giving rise to new quantum properties in a new type of magnetic metal. The ‘spin’ of the electrons has been shown to be the source of magnetism. […]
Physicists Observe Trippy ‘Vortex Rings’ in a Magnetic Material For The First Time
Science Alert December 1, 2020 Magnetic ring vortices were predicted over 20 years ago in 1998. An international team of researchers (UK, Switzerland, Ukraine, Russia) have found vortex rings inside a tiny pillar made of the magnetic material gadolinium-cobalt intermetallic compound GdCo2. They developed an X-ray nanotomography technique to image the three-dimensional magnetization structure inside a GdCo2 bulk magnet. The vortices were paired with their topological counterparts, antivortices. They also found closed magnetic loops present in vortex-antivortex pairs. After computationally analysing these structures in the context of magnetic vorticity they figured out these were doughnut-shaped ring vortices, intersected by magnetization […]
Physicists circumvent centuries-old theory to cancel magnetic fields
Phys.org October 28, 2020 Controlling magnetism, essential for a wide range of technologies, is impaired by the impossibility of generating a maximum of magnetic field in free space. An international team of researchers (Spain, Italy, UK) circumvented the limits to shape magnetic fields by creating a device comprised of a careful arrangement of electrical wires. This creates additional fields that counter act the effects of the unwanted magnetic field. While a similar effect has been achieved at much higher frequencies, this team has achieved the same at low frequencies and static fields—such as biological frequencies—which will unlock a host of useful […]
An electrical switch for magnetism
Phys.org August 6, 2020 Electrical control of magnetism in van der Waals ferromagnetic semiconductors is an important step in creating novel spintronic devices capable of processing and storing information. Using an electric double-layer transistor device, an international team of researchers (Singapore, UK, China) discovered that the magnetism of a magnetic semiconductor, Cr2Ge2Te6, shows exceptionally strong response to applied electric fields. With electric fields applied, the material was found to exhibit ferromagnetism at temperatures up to 200 K (-73°C). At such temperatures, ferromagnetic order is normally absent in this material. Their analysis suggests that heavy doping promotes a double-exchange mechanism that […]