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The anomalous magnetic moment of the electron a e measured in a Penning trap occupies a unique position among high precision measurements of physical constants in the sense that it can be compared directly with the theoretical calculation based on the renormalized quantum electrodynamics (QED) to high orders of perturbation expansion in the fine structure constant α , with an effective parameter α / π . Both numerical and analytic evaluations of a e up to ( α / π ) 4 are firmly established. The coefficient of ( α / π ) 5 has been obtained recently by an extensive numerical integration. The contributions of hadronic and weak interactions have also been estimated. The sum of all these terms leads to a e ( theory ) = 1 159 652 181.606 ( 11 ) ( 12 ) ( 229 ) × 10 − 12 , where the first two uncertainties are from the tenth-order QED term and the hadronic term, respectively. The third and largest uncertainty comes from the current best value of the fine-structure constant derived from the cesium recoil measurement: α − 1 ( Cs ) = 137.035 999 046 ( 27 ) . The discrepancy between a e ( theory ) and a e ( ( experiment ) ) is 2.4 σ . Assuming that the standard model is valid so that a e (theory) = a e (experiment) holds, we obtain α − 1 ( a e ) = 137.035 999 1496 ( 13 ) ( 14 ) ( 330 ) , which is nearly as accurate as α − 1 ( Cs ) . The uncertainties are from the tenth-order QED term, hadronic term, and the best measurement of a e , in this order.

Emergent ferromagnetism on the surface of two-dimensional (2D) MXene is investigated by X-ray magnetic circular dichroism (XMCD) and angle-dependent hard X-ray photoemission spectroscopy (HAXPES). Focusing on Cr N as one of the 2D-MXenes, high quality bilayers of Cr N/Co and Cr N/Pt are prepared by a magnetron sputtering technique. XMCD reveals the induced magnetic moment of Cr in the Cr N/Co interface, while it is not observed in the Cr N/Pt interface at room temperature. In order to distinguish the possible origins of either the interlayer magnetic exchange coupling or the charge transfer model as the source of ferromagnetism at the interface, the additional controlled Cr N/Cu bilayer, whose work function of Cu is consistent with Co, is prepared. HAXPES spectra for the Cr 2 core level near the interface of Cr N/Cu are consistent with that of Cr N/Co, indicating that the induced magnetic moment of Cr observed by XMCD for Cr N/Co can be attributed to the model of interlayer magnetic exchange coupling, rather than the charge transfer model, leading to emergent ferromagnetism at the interface with 2D-MXene.

The presence, or otherwise, of magnetism in graphene has been the subject of much debate. A systematic study of point defects—a widely suggested source of ferromagnetism in graphene—suggests that although they can exhibit net spin, they remain paramagnetic, even at liquid helium temperature. The possibility to induce a magnetic response in graphene by the introduction of defects has been generating much interest, as this would expand the already impressive list of its special properties and allow novel devices where charge and spin manipulation could be combined. So far there have been many theoretical studies (for reviews, see refs  1 , 2 , 3 ) predicting that point defects in graphene should carry magnetic moments μ ∼ μ B and these can in principle couple (anti)ferromagnetically 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 . However, experimental evidence for such magnetism remains both scarce and controversial 13 , 14 , 15 , 16 . Here we show that point defects in graphene—(1) fluorine adatoms in concentrations x gradually increasing to stoichiometric fluorographene CF x =1.0 (ref. 17 ) and (2) irradiation defects (vacancies)—carry magnetic moments with spin 1/2. Both types of defect lead to notable paramagnetism but no magnetic ordering could be detected down to liquid helium temperatures. The induced paramagnetism dominates graphene’s low-temperature magnetic properties, despite the fact that the maximum response we could achieve was limited to one moment per approximately 1,000 carbon atoms. This limitation is explained by clustering of adatoms and, for the case of vacancies, by the loss of graphene’s structural stability. Our work clarifies the controversial issue of graphene’s magnetism and sets limits for other graphitic compounds.

Single magnetic atoms on non-magnetic surfaces have magnetic moments that are usually destabilized within a microsecond, too speedily to be useful, but here the magnetic moments of single holmium atoms on a highly conductive metallic substrate can reach lifetimes of the order of minutes. Memory in a moment The magnetic moments of individual magnetic atoms are attractive components for both memory and quantum computing applications. But interactions between such atoms and the substrates on which they are mounted tend to destabilize the magnetic moments, giving them lifetimes of typically less than a few milliseconds. Toshio Miyamachi and colleagues have now identified a system consisting of single atoms of the lanthanide series rare earth element holmium on a highly conductive surface, in which intrinsic symmetries related to the properties of both the atom and the substrate combine to minimize these destabilizing interactions. As a result, the magnetic moments of the atoms can achieve lifetimes of several minutes. Single magnetic atoms, and assemblies of such atoms, on non-magnetic surfaces have recently attracted attention owing to their potential use in high-density magnetic data storage and as a platform for quantum computing 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 . A fundamental problem resulting from their quantum mechanical nature is that the localized magnetic moments of these atoms are easily destabilized by interactions with electrons, nuclear spins and lattice vibrations of the substrate 3 , 4 , 5 . Even when large magnetic fields are applied to stabilize the magnetic moment, the observed lifetimes remain rather short 5 , 6 (less than a microsecond). Several routes for stabilizing the magnetic moment against fluctuations have been suggested, such as using thin insulating layers between the magnetic atom and the substrate to suppress the interactions with the substrate’s conduction electrons 2 , 3 , 5 , or coupling several magnetic moments together to reduce their quantum mechanical fluctuations 7 , 8 . Here we show that the magnetic moments of single holmium atoms on a highly conductive metallic substrate can reach lifetimes of the order of minutes. The necessary decoupling from the thermal bath of electrons, nuclear spins and lattice vibrations is achieved by a remarkable combination of several symmetries intrinsic to the system: time reversal symmetry, the internal symmetries of the total angular momentum and the point symmetry of the local environment of the magnetic atom.

In a Wilberforce pendulum, two mechanical oscillators are coupled: one pertains to the longitudinal (tension) motion and the other to the rotational (twisting) motion. It is shown that the longitudinal magnetic moment of circular currents, and similarly the magnetic moment of a spin-chain, can exhibit a Wilberforce-like vibration. The longitudinal oscillation is related to the Langevin diamagnetism, while the twisting motion is superimposed on the magnetic moment and spin precession. The calculations show that the coupling term is nonlinear in this (longitudinal) vibrating and (magnetic moment) precession system. By increasing the strength of the coupling we arrive at a spectrum, where further vibrational modes can be associated with the rotation of the precession. This means that the extent of the change in coherence can be demonstrated. Since the coupling strength can be different due to local effects, this can be an important factor from the point of view of signal propagation and in preserving signal shapes. The amount specifying the dissipation is introduced to express the degree of deviation. A relationship exists between the parameter characteristic of the coupling strength and how its quantity influences decoherence and dissipation.

Based on the equations of electrodynamics and the concept of a critical state for hard superconductors of the 2nd kind, numerical simulation of the magnetic properties of axisymmetric superconducting samples, in particular, granules, is performed for a number of models of the dependence of the critical current density on the magnetic field induction. The magnetic moment loops are calculated directly by integrating the integral equation for the current density over time. The phenomena of the peak effect and the asymmetry of the magnetization hysteresis loop are also considered using the indicated equation. Various versions of the functions used in the literature were used as peak functions. In addition to the hysteresis loop of the magnetic moment, the magnetic field induction at the center of axisymmetric samples, and the total penetration field, the profiles of the critical current density J c ( B ) and the equilibrium magnetic moment for spherical granules were obtained. The method used for calculating the magnetic moment of superconductors makes it possible to take into account the equilibrium and nonequilibrium regions of the magnetization of the samples independently.

There discovered the maximum possible magnetic induction in nature, equal to the magnetic induction at the poles of an electron’s spin, When the spin magnetic moments of two electrons are close to each other, they act on each other with the maximum possible magnetic induction, and finally entered the maximally entangled state after the energy drops. By this time, the spin magnetic moments on both sides situated in anti-parallel, between them there existed four invisible magnetic circuit, and each magnetic circuit just contain a fluxon. No matter how far the distance between the spins, owing to the inalienability of fluxon, no magnetic flux leakage (coupling degree 100%), so these four magnetic circuit will always existed, maintaining the maximally entangled state system immutably. This is the material basis for the entangled state to be existed, nothing to do with “spooky action at a distance”. In this paper, a visual schematic diagram has drawn to describe these, and the magnetic force state, force relationship and “light barrier” problem are analyzed.

The author has for many years kept a watching brief on the experimental study of nuclear electro-magnetic moments. Accurate values of nuclear magnetic dipole and electric quadrupole moments are a major product and the life blood of hyperfine interaction studies and their manifold applications. This paper outlines recent changes in the type of moment measurements being undertaken and the effect of modern complex electronic configuration computation on the extracted moment values.

A deep insight into the electronic, structural, and magnetic properties of single-phase polycrystalline La 2 Ni 1- x Fe x MnO 6 double perovskites has been presented. X-ray photoelectron spectroscopy revealed that the Fe substitution resulted in a mixed-valence state for Ni and Mn in all samples. Rietveld analysis of the powder X-ray diffraction data suggested that all samples exhibited the orthorhombic structure with the Pbnm space group. Raman spectroscopy measurements indicated an increase in disorder of the system with Fe doping. The mixed-valence states and the accompanied disorder enhanced the competing magnetic exchange interactions in the samples resulting in a reduction of the ferromagnetic phase transition temperatures and saturation magnetic moments of the system.

This study presents an unmanned aerial vehicle (UAV)-borne vector magnetometer (MAG) system and proposes a new data-processing technique for modeling the residual magnetic anomalies of three types of landmines: the metallic antitank M15, the metallic antipersonnel M16, and the minimum-metal antitank M19. The burial depth and magnetic moment of these landmines were estimated using the measured and simulated residual magnetic anomalies based on the proposed UAV-borne vector MAG model. Initial in-flight validation showed a strong correlation between the residual magnetic anomaly maps obtained from measurements and simulations. To verify the detection capability in real-world conditions, the UAV-borne MAG system was tested at the Korean Combat Training Center. Both simulations and experiments demonstrated the effectiveness of the proposed data-processing method and UAV-borne MAG model in accurately modeling the residual magnetic anomalies of landmines with metallic components. This approach will facilitate the automated detection of M15, M16, and M19 landmines with high detection rates and enable accurate classification.