Evidence is presented for a first-order magnetic phase transition in a gated two-dimensional semiconductor, monolayer-MoS_{2}. The phase boundary separates a ferromagnetic phase at low electron density and a paramagnetic phase at high electron density. Abrupt changes in the optical response signal an abrupt change in the magnetism. The magnetic order is thereby controlled via the voltage applied to the gate electrode of the device. Accompanying the change in magnetism is a large change in the electron effective mass.
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http://dx.doi.org/10.1103/PhysRevLett.124.187602 | DOI Listing |
Phys Rev Lett
December 2024
Johns Hopkins University, Institute for Quantum Matter and Department of Physics and Astronomy, Baltimore, Maryland 21218, USA.
The tetragonal heavy-fermion superconductor CeRh_{2}As_{2} (T_{c}=0.3 K) exhibits an exceptionally high critical field of 14 T for B∥c. It undergoes a field-driven first-order phase transition between superconducting states, potentially transitioning from spin-singlet to spin-triplet superconductivity.
View Article and Find Full Text PDFHum Brain Mapp
February 2025
Department of Psychology, Ludwig Maximilian University Munich, Munich, Germany.
Accurate metacognitive judgments about an individual's performance in a mental task require the brain to have access to representations of the quality and difficulty of first-order cognitive processes. However, little is known about how accurate metacognitive judgments are implemented in the brain. Here, we combine brain stimulation with functional neuroimaging to determine the neural and psychological mechanisms underlying the frontopolar cortex's (FPC) role in metacognition.
View Article and Find Full Text PDFHeliyon
January 2025
Department of Mechanical Engineering, Faculty of Engineering, Arak University, Arak 38156-88349, Iran.
This research presents a numerical study over the unsteady natural convection of an electrically conducting fluid in an open-ended vertical parallel plate microchannel under uniform and asymmetric heat flux subjected to a uniform lateral magnetic field. Slip velocity, as well as temperature jump at channel walls, are modeled using a first-order model. The effects of Knudsen number)(, heat flux ratio)rq(, Grashof number)(, and Hartmann number)M(on mass flow rate, the maximum temperature of the wall, and average Nusselt () as a function of time are discussed.
View Article and Find Full Text PDFSci Rep
January 2025
Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA.
In a step towards generating switchable MRI cellular labels, we demonstrate in-situ field switching of micron scale metamagnetic Iron-Rhodium (FeRh) thin film particles. A thin-film (200 nm) FeRh sample was fabricated and patterned into an array of progressively smaller squares with sizes ranging from 500 μm down to 1 μm. The large first order phase change from antiferromagnetic to ferromagnetic state was characterized using vibrating sample magnetometry, magnetic force microscopy, and MRI.
View Article and Find Full Text PDFPurpose: Undifferentiated pleomorphic sarcomas (UPSs) demonstrate therapy-induced hemosiderin deposition, granulation tissue formation, fibrosis, and calcification. We aimed to determine the treatment-assessment value of morphologic tumoral hemorrhage patterns and first- and high-order radiomic features extracted from contrast-enhanced susceptibility-weighted imaging (CE-SWI).
Materials And Methods: This retrospective institutional review board-authorized study included 33 patients with extremity UPS with magnetic resonance imaging and resection performed from February 2021 to May 2023.
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