Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Itinerant-localized dichotomy in magnetic anisotropic properties of U-based ferromagnets.

ABSTRACT: The electronic structure, spin and orbital magnetic moments, and the magnetic anisotropy energy in selected U-based compounds are investigated making use of the correlated band theory. First, we demonstrate that the LSDA+U approach with exact atomic limit implemented as a combination of the relativistic density functional theory with the Anderson impurity model provides a good quantitative description for UGa[Formula: see text]. Further, the method is applied to UFe[Formula: see text] and UFe[Formula: see text]Si[Formula: see text] ferromagnets. The calculated positive uniaxial magnetic anisotropy together with negative enthalpy of formation for UFe[Formula: see text]Si[Formula: see text] make it as a candidate for the magnetically hard materials. Our studies suggest a viable route for further development of the rare-earth-lean permanent magnets by replacing a part of U atoms by some rare-earth like Sm in UFe[Formula: see text]Si[Formula: see text].

SUBMITTER: Shick AB

PROVIDER: S-EPMC9929282 | biostudies-literature | 2023 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Itinerant-localized dichotomy in magnetic anisotropic properties of U-based ferromagnets.

Shick Alexander B AB Halevy Itzhak I Tchaplianka Maxim M Legut Dominik D

Scientific reports 20230214 1

The electronic structure, spin and orbital magnetic moments, and the magnetic anisotropy energy in selected U-based compounds are investigated making use of the correlated band theory. First, we demonstrate that the LSDA+U approach with exact atomic limit implemented as a combination of the relativistic density functional theory with the Anderson impurity model provides a good quantitative description for UGa[Formula: see text]. Further, the method is applied to UFe[Formula: see text] and UFe[Fo ...[more]

PMID: 36788267

Similar Datasets

Programmable Anisotropic Hydrogels with Localized Photothermal/Magnetic Responsive Properties.

Project description:Programmable smart materials that can respond locally to specific stimuli hold great potential for many applications, but controllable fabrication of these materials remains challenging. This work reports the development of novel programmable anisotropic materials with both magnetic and photothermal stimuli-responsiveness, which are fabricated by anchoring thermosensitive poly(N-isopropyl acrylamide) (PNIPAm) and magnetic Fe3 O4 nanoparticles on the surface of MoS2 nanosheets. Further embedding PNIPAm-MoS2 /Fe3 O4 into 3D-printed hydrogel cubes results in stimuli-responsive building blocks, and the magnetic field can precisely control their orientation and near-infrared (NIR) light absorbing property. Particularly, the variation of the orientation of MoS2 /Fe3 O4 block results in obvious changes of their photothermal efficiency and optical property. By exploiting the anisotropy of MoS2 /Fe3 O4 and their NIR light responsiveness, thermally-induced phase transitions in individual 3D printed hydrogel building block can be locally controlled for magnetic field-assisted programming a quick response (QR) code. Alternatively, fluorescent QR code with high contrast and security level can be achieved by photothermal-induced release of fluorescent dyes. These 3D printed magnetically programmed hydrogels hold great potential for application in information storage, intelligent materials, and precise therapy.

| S-EPMC9475551 | biostudies-literature

Disparate ultrafast dynamics of itinerant and localized magnetic moments in gadolinium metal.

Project description:The Heisenberg-Dirac intra-atomic exchange coupling is responsible for the formation of the atomic spin moment and thus the strongest interaction in magnetism. Therefore, it is generally assumed that intra-atomic exchange leads to a quasi-instantaneous aligning process in the magnetic moment dynamics of spins in separate, on-site atomic orbitals. Following ultrashort optical excitation of gadolinium metal, we concurrently record in photoemission the 4f magnetic linear dichroism and 5d exchange splitting. Their dynamics differ by one order of magnitude, with decay constants of 14 versus 0.8 ps, respectively. Spin dynamics simulations based on an orbital-resolved Heisenberg Hamiltonian combined with first-principles calculations explain the particular dynamics of 5d and 4f spin moments well, and corroborate that the 5d exchange splitting traces closely the 5d spin-moment dynamics. Thus gadolinium shows disparate dynamics of the localized 4f and the itinerant 5d spin moments, demonstrating a breakdown of their intra-atomic exchange alignment on a picosecond timescale.

| S-EPMC4579838 | biostudies-literature

Inkjet Printing of Magnetic Particles Toward Anisotropic Magnetic Properties.

Project description:Unique properties of one-dimensional assemblies of particles have attracted great attention during the past decades, particularly with respect to the potential for anisotropic magnetism. Patterned films can be created using inkjet printing; however, drying of particle-laden colloidal droplets on solid surfaces is usually accompanied by the well-known coffee-ring effect, deteriorating both the uniformity and resolution of the printed configurations. This study examines the effect of externally applied magnetic field on particle deposition patterns. Ferromagnetic Gd5Si4 particles were formulated in terpineol oil and directly deposited via magnetic field-assisted inkjet printing on a photopaper to generate patterned films with suppressed coffee-ring effect. The particle deposition morphology is determined by both solvent imbibition and particle-magnetic field interactions. Three characteristic times are considered, namely, the critical time for solvent imbibition into the substrate (tim), the time it takes for particles to form chains in the presence of the magnetic field (tch), and the time in which the particles reach the substrate in the direction normal to the substrate (tpz). The characteristic time ratios (tpz/tim) and (tpz/tch) determine the final deposition morphology in the presence of magnetic field. The ability to control particle deposition and assembly, thus tuning the magnetic anisotropic properties of nanostructured materials is a promising approach for many engineering applications.

| S-EPMC6838153 | biostudies-literature

Complex magnetic properties associated with competing local and itinerant magnetism in [Formula: see text].

Project description:Ternary intermetallic compound [Formula: see text] has been synthesized in single phase and characterized by x-ray diffraction, scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM-EDX) analysis, magnetization, heat capacity, neutron diffraction and muon spin rotation/relaxation ([Formula: see text]SR) measurements. The polycrystalline compound was synthesized in single phase by introducing necessary vacancies in Co/Si sites. Magnetic, heat capacity, and zero-field neutron diffraction studies reveal that the system undergoes magnetic transition below [Formula: see text]4 K. Neutron diffraction measurement further reveals that the magnetic ordering is antiferromagnetic in nature with an weak ordered moment. The high temperature magnetic phase has been attributed to glassy in nature consisting of ferromagnetic clusters of itinerant (3d) Co moments as evident by the development of internal field in zero-field [Formula: see text]SR below 50 K. The density-functional theory (DFT) calculations suggest that the low temperature magnetic transition is associated with antiferromagnetic coupling between Pr 4f and Co 3d spins. Pr moments show spin fluctuation along with unconventional orbital moment quenching due to crystal field. The evolution of the symmetry and the crystalline electric field environment of Pr-ions are also studied and compared theoretically between the elemental Pr and when it is coupled with other elements such as Co. The localized moment of Pr 4f and itinerant moment of Co 3d compete with each other below [Formula: see text]20 K resulting in an unusual temperature dependence of magnetic coercivity in the system.

| S-EPMC8225917 | biostudies-literature

On anisotropic mechanical properties of heterogeneous magnetic polymeric composites.

Project description:This study is devoted to the magneto-mechanical characterization of heterogeneous magnetoactive elastomers based on an elastic polydimethylsiloxane matrix with embedded spherical magnetic soft microparticles and magnetic hard microparticles of irregular shape. An issue of the anisotropic mechanical properties of these smart composites is considered. Non-magnetized and pre-magnetized specimens are characterized using a planar shear and axial loading in an externally applied homogeneous magnetic field. The field direction differs relative to the direction of the field used for the specimens pre-magnetization. Results of the different methods allow comparison of the tensile shear moduli for the samples with an initially identical composition. Obtained results demonstrate a strong correlation between the composite behaviour and orientation of the magnetic field used for the pre-magnetization of the sample relative to the external field applied to a sample during the test. Composites pre-magnetized in the direction parallel to an applied mechanical force and external magnetic field show higher magnetorheological response than composites pre-magnetized transversally to the force and the field. Application of the external field directed opposite to the direction of the pre-magnetization reduces the observed stiffening. Moreover, in this situation a softening of the material can be observed, depending on the magnitude of the external field and the field used for pre-magnetization. This article is part of the theme issue 'Heterogeneous materials: metastable and non-ergodic internal structures'.

| S-EPMC6460060 | biostudies-literature

An itinerant antiferromagnetic metal without magnetic constituents.

Project description:The origin of magnetism in metals has been traditionally discussed in two diametrically opposite limits: itinerant and local moments. Surprisingly, there are very few known examples of materials that are close to the itinerant limit, and their properties are not universally understood. In the case of the two such examples discovered several decades ago, the itinerant ferromagnets ZrZn2 and Sc3In, the understanding of their magnetic ground states draws on the existence of 3d electrons subject to strong spin fluctuations. Similarly, in Cr, an elemental itinerant antiferromagnet with a spin density wave ground state, its 3d electron character has been deemed crucial to it being magnetic. Here, we report evidence for an itinerant antiferromagnetic metal with no magnetic constituents: TiAu. Antiferromagnetic order occurs below a Néel temperature of 36 K, about an order of magnitude smaller than in Cr, rendering the spin fluctuations in TiAu more important at low temperatures. This itinerant antiferromagnet challenges the currently limited understanding of weak itinerant antiferromagnetism, while providing insights into the effects of spin fluctuations in itinerant-electron systems.

| S-EPMC4510670 | biostudies-literature

Superconducting imprint of magnetic textures in ferromagnets with perpendicular magnetic anisotropy.

Project description:Research on proximity effects in superconductor/ferromagnetic hybrids has most often focused on how superconducting properties are affected-and can be controlled-by the effects of the ferromagnet's exchange or magnetic fringe fields. The opposite, namely the possibility to craft, tailor and stabilize the magnetic texture in a ferromagnet by exploiting superconducting effects, has been more seldom explored. Here we show that the magnetic flux trapped in high-temperature superconducting YBa2Cu3O7-δ microstructures can be used to modify the magnetic reversal of a hard ferromagnet-a cobalt/platinum multilayer with perpendicular magnetic anisotropy-and to imprint unusual magnetic domain distributions in a controlled manner via the magnetic field history. The domain distributions imprinted in the superconducting state remain stable, in absence of an external magnetic field, even after increasing the temperature well above the superconducting critical temperature, at variance to what has been observed for soft ferromagnets with in-plane magnetic anisotropy. This opens the possibility of having non-trivial magnetic configuration textures at room temperature after being tailored below the superconducting transition temperature. The observed effects are well explained by micromagnetic simulations that demonstrate the role played by the magnetic field from the superconductor on the nucleation, propagation, and stabilization of magnetic domains.

| S-EPMC8531309 | biostudies-literature

Local dynamics of topological magnetic defects in the itinerant helimagnet FeGe.

Project description:Chiral magnetic interactions induce complex spin textures including helical and conical spin spirals, as well as particle-like objects such as magnetic skyrmions and merons. These spin textures are the basis for innovative device paradigms and give rise to exotic topological phenomena, thus being of interest for both applied and fundamental sciences. Present key questions address the dynamics of the spin system and emergent topological defects. Here we analyse the micromagnetic dynamics in the helimagnetic phase of FeGe. By combining magnetic force microscopy, single-spin magnetometry and Landau-Lifschitz-Gilbert simulations we show that the nanoscale dynamics are governed by the depinning and subsequent motion of magnetic edge dislocations. The motion of these topologically stable objects triggers perturbations that can propagate over mesoscopic length scales. The observation of stochastic instabilities in the micromagnetic structure provides insight to the spatio-temporal dynamics of itinerant helimagnets and topological defects, and discloses open challenges regarding their technological usage.

| S-EPMC4992142 | biostudies-literature

Quantum Magnetic Properties in Perovskite with Anderson Localized Artificial Spin-1/2.

Project description:Quantum magnetic properties in a geometrically frustrated lattice of spin-1/2 magnet, such as quantum spin liquid or solid and the associated spin fractionalization, are considered key in developing a new phase of matter. The feasibility of observing the quantum magnetic properties, usually found in geometrically frustrated lattice of spin-1/2 magnet, in a perovskite material with controlled disorder is demonstrated. It is found that the controlled chemical disorder, due to the chemical substitution of Ru ions by Co-ions, in a simple perovskite CaRuO3 creates a random prototype configuration of artificial spin-1/2 that forms dimer pairs between the nearest and further away ions. The localization of the Co impurity in the Ru matrix is analyzed using the Anderson localization formulation. The dimers of artificial spin-1/2, due to the localization of Co impurities, exhibit singlet-to-triplet excitation at low temperature without any ordered spin correlation. The localized gapped excitation evolves into a gapless quasi-continuum as dimer pairs break and create freely fluctuating fractionalized spins at high temperature. Together, these properties hint at a new quantum magnetic state with strong resemblance to the resonance valence bond system.

| S-EPMC5980209 | biostudies-literature

Possible observation of highly itinerant quantum magnetic monopoles in the frustrated pyrochlore Yb2Ti2O7.

Project description:The low-energy elementary excitations in frustrated quantum magnets have fascinated researchers for decades. In frustrated Ising magnets on a pyrochlore lattice possessing macroscopically degenerate spin-ice ground states, the excitations have been discussed in terms of classical magnetic monopoles, which do not contain quantum fluctuations. Here we report unusual behaviours of magneto-thermal conductivity in the disordered spin-liquid regime of pyrochlore Yb2Ti2O7, which hosts frustrated spin-ice correlations with large quantum fluctuations owing to pseudospin-1/2 of Yb ions. The analysis of the temperature and magnetic field dependencies shows the presence of gapped elementary excitations. We find that the gap energy is largely suppressed from that expected in classical monopoles. Moreover, these excitations propagate a long distance without being scattered, in contrast to the diffusive nature of classical monopoles. These results suggests the emergence of highly itinerant quantum magnetic monopole, which is a heavy quasiparticle that propagates coherently in three-dimensional spin liquids.

| S-EPMC4773418 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data