In this work, the advantages of X-Band lead us to extract and study the electric and magnetic properties of Nickel (Ni) doped Zinc Oxide (ZnO) nanoparticles (NPs). So as to attain the proposed ...characteristics, waveguide measurement approach has been performed. And in order to extract the stated properties such as permittivity and permeability from the scattering parameters, Nicolson-Ross-Weir method has been utilized. Hence, both capacitance and inductance behaviors have been observed through the attained complex impedance considering the response of the Ni–ZnO NPs to the electromagnetic wave incident. Subsequently, results show that inductance, capacitance and resistance behaviors of Ni–ZnO NPs change around the two main resonance frequencies (8.767 GHz and 10.47 GHz). The attained magnetic susceptibility characteristic confirms that the Ni–ZnO NPs is ferromagnetic over the frequency of 8–9.746 GHz and paramagnetic up to 12.5 GHz.
The electronic and magnetic properties of single 3d transition-metal (TM) atom (V, Cr, Mn, Fe, Co, and Ni) adsorbed graphdiyne (GDY) and graphyne (GY) are systematically studied using density ...functional theory (DFT). It is found that the electronic structures of TM-GDY/GY are sensitive to the value of the on-site Coulomb energy for the TM 3d orbital. It is crucial to use DFT+U method and accurately account for the electron correlation in the calculations. By using linear response method, we are able to determine the U eff value for all TM adatom. We find that the adsorption of TM atom not only efficiently modulates the electronic structures of GDY/GY system but also introduces excellent magnetic properties, such as spin-polarized half-semiconductor. Such modulation originates from the charge transfer between TM adatom and GDY/GY sheet as well as the electron redistribution of the TM intra-atomic s, p, and d orbitals. Our results indicate that the TM adsorbed GDY/GY are excellent candidates for spintronics.
YBaCo.sub.4O.sub.7 +.sub.x Kazei, Z. A; Markina, M. M; Snegirev, V. V ...
Journal of experimental and theoretical physics,
07/2023, Letnik:
137, Številka:
1
Journal Article
The modification of magnetic and elastic properties of YBaCo.sub.4O.sub.7 +.sub.x (x = 0, 0.1) cobaltites at a slight controlled deviation from stoichiometry (x) has been investigated. The magnetic ...properties of stoichiometric YBaCo.sub.4O.sub.7 demonstrate nontrivial behavior, which is inconsistent with the generally accepted notion of phase transitions with long-range magnetic order. Only magnetic moment DELTAM = M.sub.FC - M.sub.ZFC induced by an external magnetic field (an analog of thermoremanent magnetization) exhibits anomalies at magnetic phase transition temperatures T.sub.N1 and T.sub.N2 that coincide with those of Young's modulus anomalies, whereas in the magnetic susceptibility curves taken in the FC and ZFC modes, phase transitions are not discerned. At a small off-stoichiometry (x = 0.1), induced moment DELTAM rises by an order of magnitude and a residual ferromagnetic moment of about 10.sup.-3 mu.sub.B arises in the magnetization curves. Two scenarios of the cobalt subsystem magnetic behavior with increasing part of cobalt ions Co.sup.3+ have been discussed. It has been found that when YBaCo.sub.4O.sub.7 +.sub.x cobaltites deviate from stoichiometry, the evolution of their magnetic properties is similar to that observed at the transition from Y-based to Ca-based cobaltite.
•High-quality inorganic insulating layer was performed for industrial Fe-based amorphous flaky powders.•FeSiBCCr MFPCs show better magnetic properties and lower raw material cost than the Finemet ...MFPCs.•The FeSiBCCr MFPCs exhibit higher permeability and lower core loss than conventional FeSiB MFPCs.•The FeSiBCCr MFPCs annealed at 773 K for 0.5 h exhibit excellent comprehensive soft magnetic properties.
Fe-based amorphous powder cores based on the industrial flaky FeSiBCCr magnetic powders coated with high-quality inorganic (SiO2) insulating layer via a sol-gel method were successfully fabricated to improve the soft magnetic properties of powder cores. The core-shell structure of magnetic flaky powders was characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy analysis, and Fourier transform infrared spectroscopy. The influence of annealing temperature on the soft magnetic properties of the FeSiBCCr magnetic flaky powder cores (MFPCs) has been systematically investigated, and the comparisons were made with the conventional FeSiB and Finemet MFPCs at the same preparation conditions. It was found that the reasonable annealing temperature could enhance the permeability and reduce the core loss for the MFPCs. As compared to the conventional FeSiB MFPCs, the FeSiBCCr MFPCs annealed at 773 K for 0.5 h exhibits a higher permeability of 79.19, and lower core loss of 122.26 mW/m3 at 100 kHz for Bm = 0.05 T. Additionally, the FeSiBCCr MFPCs shows a better DC-bias property of 51.30%, and lower raw material cost than those of the Finemet MFPCs. The excellent comprehensive magnetic properties of the FeSiBCCr MFPCs are favorable for achieving the optimal design of powder cores toward practical applications.
Strain engineering is widely used to manipulate the electronic and magnetic properties of complex materials. For example, the piezomagnetic effect provides an attractive route to control magnetism ...with strain. In this effect, the staggered spin structure of an antiferromagnet is decompensated by breaking the crystal field symmetry, which induces a ferrimagnetic polarization. Piezomagnetism is especially appealing because, unlike magnetostriction, it couples strain and magnetization at linear order, and allows for bi-directional control suitable for memory and spintronics applications. However, its use in functional devices has so far been hindered by the slow speed and large uniaxial strains required. Here we show that the essential features of piezomagnetism can be reproduced with optical phonons alone, which can be driven by light to large amplitudes without changing the volume and hence beyond the elastic limits of the material. We exploit nonlinear, three-phonon mixing to induce the desired crystal field distortions in the antiferromagnet CoF2. Through this effect, we generate a ferrimagnetic moment of 0.2 μB per unit cell, nearly three orders of magnitude larger than achieved with mechanical strain.This paper shows how lattice distortions induced by a laser pulse can create a ferrimagnetic moment in an antiferromagnet. This mechanism gives a magnetic response that is orders of magnitude larger than using mechanical strain.
Structural, optical and magnetic properties of NiCexFe2axO4 (x=0.0a0.10) nanoparticles prepared by the chemical route, have been studied. All the samples exhibit pure spinel phase except that with ...x=0.10. Crystallite size decreases gradually from 57 to 17 nm as the Ce concentration increases from 0 to 0.10. Fourier transform infrared spectroscopy shows that in comparison to pure nickel ferrite, the bands corresponding to FeaO vibration are shifted towards higher wave number after doping with Ce. The Mossbauer spectra for all the compositions show the presence of two sextets at room temperature showing the ferrimagnetic character of the samples. Magnetic hysteresis curves show that the saturation magnetisation changes from a1441.8 emu/g for pure nickel ferrite to a1431.6 emu/g after doping with Ce=0.10. However, the variation of magnetic moment with Ce concentration is irregular. The cation distribution in the samples shows the mixed spinel structure.
Gravitational interactions between the Large Magellanic Cloud (LMC) and the stellar and dark matter halo of the Milky Way are expected to give rise to disequilibrium phenomena in the outer Milky Way
.... A local wake is predicted to trail the orbit of the LMC, and a large-scale overdensity is predicted to exist across a large area of the northern Galactic hemisphere. Here we report the detection of both the local wake and northern overdensity (hereafter the 'collective response') in a map of the Galaxy based on 1,301 stars at Galactocentric distances between 60 and 100 kiloparsecs. The location of the wake is in good agreement with an N-body simulation that includes the dynamical effect of the LMC on the Milky Way halo. The density contrast of the wake and collective response are stronger in the data than in the simulation. The detection of a strong local wake is independent evidence that the Magellanic clouds are on their first orbit around the Milky Way. The wake traces the path of the LMC, which will provide insight into the orbit of the LMC, which in turn is a sensitive probe of the mass of the LMC and the Milky Way. These data demonstrate that the outer halo is not in dynamical equilibrium, as is often assumed. The morphology and strength of the wake could be used to test the nature of dark matter and gravity.
Lanthanide supramolecular chemistry is a fast growing and intriguing research field due to the unique photophysical, magnetic, and coordination properties of lanthanide ions (LnIII). Compared with ...the intensively investigated mononuclear Ln-complexes, polymetallic lanthanide supramolecular assemblies offer more structural superiority and functional advantages. In recent decades, significant progress has been made in polynuclear lanthanide supramolecules, varying from structural evolution to luminescent and magnetic functional materials. This review summarizes the design principles in ligand-induced coordination-driven self-assembly of polynuclear Ln-structures and intends to offer guidance for the construction of more elegant Ln-based architectures and optimization of their functional performances. Design principles concerning the water solubility and chirality of the lanthanide-organic assemblies that are vital in extending their applications are emphasized. The strategies for improving the luminescent properties and the applications in up-conversion, host–guest chemistry, luminescent sensing, and catalysis have been summarized. Magnetic materials based on supramolecular assembled lanthanide architectures are given in an individual section and are classified based on their structural features. Challenges remaining and perspective directions in this field are also briefly discussed.
We detected the spin polarization due to charge flow in the spin nondegenerate surface state of a three-dimensional topological insulator by means of an all-electrical method. The charge current in ...the bulk-insulating topological insulator Bi1.5Sb0.5Te1.7Se1.3 (BSTS) was injected/extracted through a ferromagnetic electrode made of Ni80Fe20, and an unusual current-direction-dependent magnetoresistance gave evidence for the appearance of spin polarization, which leads to a spin-dependent resistance at the BSTS/Ni80Fe20 interface. In contrast, our control experiment on Bi2Se3 gave null result. These observations demonstrate the importance of the Fermi-level control for the electrical detection of the spin polarization in topological insulators.
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