Publications by authors named "Y Sidis"

High-Entropy Alloys (HEAs) are a new family of crystalline random alloys with four or more elements in a simple unit cell, at the forefront of materials research for their exceptional mechanical properties. Their strong chemical disorder leads to mass and force-constant fluctuations which are expected to strongly reduce phonon lifetime, responsible for thermal transport, similarly to glasses. Still, the long range order would associate HEAs to crystals with a complex disordered unit cell.

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Spin-orbit coupling (SOC) is a key to understand the magnetically driven superconductivity in iron-based superconductors, where both local and itinerant electrons are present and the orbital angular momentum is not completely quenched. Here, we report a neutron scattering study on the bilayer compound CaK(Fe_{0.96}Ni_{0.

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Article Synopsis
  • 5d iridium oxides, like strontium iridate (Sr₂IrO₄), are being studied for potential new quantum states due to strong spin-orbit coupling and an unconventional Mott insulating state.
  • Researchers used polarized neutron diffraction to measure the magnetization density in Sr₂IrO₄, revealing that its distribution is anisotropic and aspherical, differing from the expected j_{eff}=1/2 model.
  • The study found that the magnetization density showed a dominant xy orbital contribution, suggesting that the relationship to superconducting copper oxides may not be as strong as previously believed.
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Congenital hypogonadotropic hypogonadism (CHH) is a rare genetic disorder characterized by infertility and the absence of puberty. Defects in GnRH neuron migration or altered GnRH secretion and/or action lead to a severe gonadotropin-releasing hormone (GnRH) deficiency. Given the close developmental association of GnRH neurons with the olfactory primary axons, CHH is often associated with anosmia or hyposmia, in which case it is defined as Kallmann syndrome (KS).

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The magnon dispersion of ferromagnetic SrRuO_{3} was studied by inelastic neutron scattering experiments on single crystals as a function of temperature. Even at low temperature the magnon modes exhibit substantial broadening pointing to strong interaction with charge carriers. We find an anomalous temperature dependence of both the magnon gap and the magnon stiffness, which soften upon cooling in the ferromagnetic phase.

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