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Background: Eddy current damper (ECD) pledges better control over damping coefficient, provides contactless damping, requires little or no maintenance, has simpler construction, no performance degradation over time, and is cost-effective as compared to mechanical dampers. Its challenge includes the development of a system which provides comparable damping density to other mechanical systems for structural applications. Purpose: ECD has the potential to protect common structures in seismically active areas at low cost and with better vibration control. Further, the application of such dampers may protect industrial assembly structures against undesirable fatigue and increase the lifespan of structures that are constantly prone to vibrations. Methods: This paper produces a review of existing literature in vibration control of structures equipped with ECDs, types of ECDs developed for structural applications, SDOF (single degree of freedom) benchmark structure equipped with ECD, challenges, and opportunities in the development of ECD therein. [ABSTRACT FROM AUTHOR]

Understanding the origin and mechanisms of magnetic damping in complex oxide materials is crucial for optimizing spin dynamics and tailoring their properties for specific spintronic applications. Ferromagnetic resonance spectroscopy (FMR) technique has been used to investigate the magnetic damping of multiple La2/3Sr1/3MnO3 (LSMO) epitaxial thin films with similar thickness and identical DC magnetic properties. However, the dynamic magnetic properties exhibit noticeable variations among samples. Microstructural analyses using X-ray diffraction (XRD) and atomic force microscopy (AFM), confirm that the samples are structurally identical, except for minute differences in the miscut angles of the substrates. Nevertheless, when examining the samples using backscattered electron (BSE) images in scanning electron microscopy (SEM), significant disparities in the twin distribution are observed. These variations in the twin distribution directly correlate with the observed differences in the damping values. A careful image analysis of BSE images allows to demonstrate that the increase of damping is due to the pinning of the magnetization in the twin boundaries. [ABSTRACT FROM AUTHOR]

Half-metallic chromium dioxide (CrO2) is a promising candidate in magnetic random-access memory (MRAM) devices due to its nearly full spin polarization and ultralow Gilbert damping at room temperature. In this study, we succeeded in fabricating (110) and (100)-oriented RuO2/CrO2 bilayers with different thicknesses of CrO2 film using two-step method. The CrO2 film epitaxially grown on a RuO2 layer exhibits a perfect in-plane magnetic uniaxial anisotropy. The magnetic relaxation of CrO2 films can be strongly modulated via the proximity to RuO2 layer, which may relate to the enhancement of the two-magnon scattering due to effects of antiferromagnetic order in RuO2 film. In addition, electronic transport measurements indicate that the electronic characteristic is strongly related to the film growth orientation, and a linear magnetoresistance is observed stemming from intergrain tunneling magnetoresistance and double-exchange mechanism. Angle-dependent ferromagnetic resonance measurements indicates that the uniaxial anisotropy in CrO2 film is strongly related to the strain effect, which is consistent with reciprocal space mapping results. This work lays a foundation for current-drive MRAM based on RuO2/CrO2 bilayer and provides a feasible damping modulation method for CrO2 film.

Both the ferromagnetic and exchange resonance modes were investigated in the ferrimagnetic Gdx(Co80Fe20)100–x nanoscale thin films by using an all-optical pump–probe technique. We observed that the ferromagnetic resonance frequency fFMR significantly increases in the vicinity of the angular momentum compensation point CA as well as the effective g-factor geff and Gilbert damping parameter αs, which could be fitted well with the theoretical calculation by the Kittel equation. Unconventionally, the exchange resonance mode only appears in the range of 25 at. % ≤ x ≤ 27 at. % (Gd-rich) near CA. The exchange resonance frequency fexch shows a monotonic increase with increasing perpendicular anisotropy constant Kz. We report the experimental and theoretical investigations that the fexch not only depends on both the net angular moment and pump-laser fluence but is also dominated by the Kz. [ABSTRACT FROM AUTHOR]

Following the demonstration of laser-induced ultrafast demagnetization in ferromagnetic nickel, several theoretical and phenomenological propositions have sought to uncover its underlying physics. In this work we revisit the three temperature model (3TM) and the microscopic three temperature model (M3TM) to perform a comparative analysis of ultrafast demagnetization in 20 nm thick cobalt, nickel and permalloy thin films measured using an all-optical pump-probe technique. In addition to the ultrafast dynamics at the femtosecond timescales, the nanosecond magnetization precession and damping are recorded at various pump excitation fluences revealing a fluence-dependent enhancement in both the demagnetization times and the damping factors. We confirm that the Curie temperature to magnetic moment ratio of a given system acts as a figure of merit for the demagnetization time, while the demagnetization times and damping factors show an apparent sensitivity to the density of states at the Fermi level for a given system. Further, from numerical simulations of the ultrafast demagnetization based on both the 3TM and the M3TM, we extract the reservoir coupling parameters that best reproduce the experimental data and estimate the value of the spin flip scattering probability for each system. We discuss how the fluence-dependence of inter-reservoir coupling parameters so extracted may reflect a role played by nonthermal electrons in the magnetization dynamics at low laser fluences. [ABSTRACT FROM AUTHOR]

• The influence of DMI on the spin wave propagation in magnetic domain wall is studied. • The DMI-induced nonreciprocal damping of spin waves is reported. • Unidirectional transportion of spin waves in magnetic domain wall is realized. The nonreciprocity of spin waves refers to the phenomenon that spin waves propagating in opposite directions display different features. This phenomen becomes a fundamental requirement for implementing magnon logic architectures. The nonreciprocal transportion of spin waves induced by Dzyaloshinskii-Moriya interaction (DMI) has been studied extensively. It is characterized by a shift of spin-wave dispersion. Here we report another feature of the DMI-induced nonreciprocity, i.e., the nonreciprocal spin wave damping. We find that the spin waves propagating with opposite wave vectors in magnetic domain wall have different damping, which is frequency dependent and especially evident in low frequancy range. For spin waves with sufficient low frequencies (around 1 GHz), the damping nonreciprocity is so extreme that spin waves can transport only in one direction, thus realizing the spin-wave diode function. The theoretical predictions are validated by micromagnetic simulations. The findings in this work points out a new feature of DMI-induced spin wave nonreciprocity and may be exploited for designing novel magnonic devices. [ABSTRACT FROM AUTHOR]

Half-metallic ferromagnets are promising in charge-based and magnon-based devices due to their high spin polarization and low Gilbert damping. In this study, a significant anisotropy in the dynamic relaxation behavior is observed in half-metallic CrO 2 films of different thicknesses. Our results indicate that the major ferromagnetic resonance linewidth stems from the contributions of two-magnon scattering (TMS) and the mosaicity effect caused by the spatial variation of the crystal axis, and the intrinsic Gilbert damping makes only a tiny contribution to the overall relaxation linewidth. Apart from the possible anisotropy of Gilbert damping, TMS and the mosaicity effect contribute to a large anisotropy of magnetic relaxation. The TMS linewidth is related to the films thickness and surface morphology when the polar angle of magnetization direction exceeds the cut-off angle for TMS. At low polar angles of external field, the dominant magnetic relaxation is the mosaicity effect resulting from spatial change of crystal axis, which leads to an exceptionally large linewidth that can reach several thousands Oersteds. [Display omitted] • The strain of epitaxial CrO 2 films are analyzed by reciprocal space mapping tests. • A large anisotropy of the dynamic relaxation is observed for half-metallic CrO 2. • The major magnetic relaxation comes from two-magnon scattering and the mosaicity effect. • The magnetic relaxation dominated by mosaicity effect can reach several thousands of Oe. [ABSTRACT FROM AUTHOR]

Perpendicular magnetic anisotropy (PMA), spin pumping-induced damping, and interfacial Dzyaloshinskii–Moriya interaction (iDMI), which are spin–orbit coupling-related phenomena of utmost importance for applications, were experimentally investigated in as-grown and 225 °C annealed CoFeB/PtOx, CoFeB/TaOx, and Ta/CoFeB/TaOx systems by means of vibrating sample magnetometry, microstrip ferromagnetic resonance, and Brillouin light scattering techniques. By varying Co8Fe72B20 (CoFeB) thickness in the range of 0.8–10 nm, the effect of Ta buffer layer on anisotropy and damping was first studied, where a large surface magnetic anisotropy ($K_{s}=2.1\,\,\pm \,\,0.16$ erg/cm2) was measured in the unbuffered CoFeB/TaOx(0.8 nm) system most likely due to their higher roughness induced by the substrate. $K_{s}$ degrades significantly for CoFeB film thickness below 2 nm where spontaneous perpendicular magnetization was found to be impossible without Ta buffer layer. PMA, iDMI, and damping of as-deposited and 225 °C annealed CoFeB (1.5 nm)/PtOx systems were measured as a function of PtOx thickness in the range of 0.7–1.6 nm. Their strong dependence versus the PtOx thickness was attributed to the decrease of the magnetic dead layer as PtOx thickness increases. Linear dependence of damping versus PMA constant was obtained, confirming their relation with the spin–orbit coupling. Moreover, annealing increases PMA and the effective mixing conductance probably due to the enhancement of the CoFeB crystal structure and interfaces. [ABSTRACT FROM AUTHOR]

A spin thermoelectric (STE) generator is composed of a thin paramagnetic metal (PM) layer, ferrimagnetic insulator (FMI) and PM/FMI bilayer interface. Various studies have been carried out on improving the characteristics of each part of this structure in order to raise the STE voltage $V_{\mathrm {STE}}$. We investigated the substitution of bismuth for yttrium and aluminum for iron to observe the characteristic changes in $V_{\mathrm {STE}}$. FMI films of epitaxial Bi-substituted iron garnets exhibit large growth-induced magnetic anisotropy perpendicular to the film surface. This anisotropy increases the magnetic damping $\alpha $ in the FMI, and the values of $\alpha $ increase with increasing Bi content. As a result, a large rise in STE voltage was observed. We report the rise in $V_{\mathrm {STE}}$ observed in an STE generator incorporating Bi-substituted yttrium iron garnet (YIG) films grown by liquid phase epitaxy (LPE) and explain the origin of the voltage rise based on the results of ferromagnetic resonance measurements. To comprehensively examine the effect of substitution on LPE YIG films, the $V_{\mathrm {STE}}$ values observed in STE generators incorporating Al-substituted YIG films are also presented. [ABSTRACT FROM AUTHOR]

Zn/Al co-doped nickel ferrites (NZAFO) with ultralow magnetic damping and large magnetostriction are critically needed for use in tunable spintronic devices and dissipationless quantum computation. However, the growth of epitaxial NZAFO thin films with optimized properties is difficult due to their tendency to form anti-site defects and antiphase boundaries, even on isostructural spinel substrate. Here, growth temperature-dependent ferromagnetic resonance (FMR) and magnetization have been systematically investigated. The saturate magnetization and damping linewidth have decreased from 114 to 70 emu/cc and 321 to 12 Oe as deposition temperature increased from 500 °C to 650 °C, respectively. With further optimization of the film thickness, a minimum FMR linewidth of 7.5 Oe has been observed, only 1.74% of that of bulk form NZAFO materials. Further increasing of deposition temperature to 700 °C results in a dramatic increase in the magnetic coercive field and damping linewidth. The magnetostriction and magnetocrystalline anisotropy are relatively stable in a large temperature range. The strong dependence between magnetic properties and the deposition temperature has been explained in terms of cation redistribution and evaporation. The insulating ferrimagnetic NZAFO with ultralow microwave loss and strain tunable static and dynamic magnetic properties serve as a promising candidate to be used in various tunable electronic devices. [ABSTRACT FROM AUTHOR]

Charge-spin interconversion processes underpin the generation of spin-orbit torques in magnetic/nonmagnetic bilayers. However, efficient sources of spin currents such as 5 d metals are also efficient spin sinks, resulting in a large increase of magnetic damping. Here we show that a partially oxidized 3 d metal can generate a strong orbital torque without a significant increase in damping. Measurements of the torque efficiency ξ and Gilbert damping α in CoFe/CuO x and CoFe/Pt indicate that ξ is comparable in the two systems. The increase in damping relative to a single CoFe layer is Δα < 0.002 in CoFe/CuOx and Δα ≈ 0.005-0.02 in CoFe/Pt, depending on CoFe thickness. We ascribe the nonreciprocal relationship between Δα and ξ in CoFe/CuO x to the small orbital-spin current ratio generated by magnetic resonance in CoFe and the lack of an efficient spin sink in CuO x . Our findings provide new perspectives on the efficient excitation of magnetization dynamics via the orbital torque.

This article reports damping enhancement in a ferromagnetic NiFe thin film due to an adjacent α‐Sn thin film. Ferromagnetic resonance studies show that an α‐Sn film separated from a NiFe film by an ultrathin Ag spacer can cause an extra damping in the NiFe film that is three times bigger than the intrinsic damping of the NiFe film. Such an extra damping is absent in structures where the α‐Sn film interfaces directly with a NiFe film, or is replaced by a β‐Sn film. The data suggest that the extra damping is associated with topologically nontrivial surface states in the topological Dirac semimetal phase of the α‐Sn film. This work suggests that, like topological insulators, topological Dirac semimetal α‐Sn may have promising applications in spintronics. [ABSTRACT FROM AUTHOR]

We investigated the effect of rare-earth (RE) element doping on magnetodynamic properties of 1D Ni80Fe20 (Py) nanowires. 5% of doping of RE element (La, Nd, and Sm) in Py nanowires was successfully done by electrodeposition technique in porous anodic alumina template. It is observed by the X-ray diffraction (XRD) measurements that the crystal structure of Py nanowires decreases from polycrystalline to amorphous phase with doping of RE element. The magnetic properties demonstrated that the saturation magnetization decreases upto 98% with the higher atomic number RE dopant. The ferromagnetic resonance measurements in field-sweep mode were done to analyze the magnetization dynamics of RE-doped nanowires. The fitting of resonance field and field linewidth was done by using the Landau–Lifshitz–Gilbert equation. It is observed that the resonance field increases with Sm doping as compared to La doping. The damping constants have been achieved by decocting the extrinsic linewidth and found to increase by ~12 times with RE doping. The increase of Gilbert damping emanates from the enhancement of L–S coupling in Py nanowires. [ABSTRACT FROM AUTHOR]

Multifunctional multiferroic materials, such as rare-earth-doped yttrium iron garnet (YIG), are advantageous for low-energy-consumption devices. In this work, we investigated aliovalent (Ce4+) substitution in Y2.9Bi0.1Fe5O12 ferrite with different compositions Y2.9-xCexBi0.1Fe5O12 ($x =0.0$ , 0.2, 0.4), respectively. The ferrites were fabricated by a conventional solid-state reaction method, and their structural, static, and dynamic magnetic properties were studied at room temperature. The X-ray diffraction (XRD) pattern confirmed the $Ia\bar {3}d$ cubic phase of all the ferrite compositions together with ceric oxide (CeO2) as a residual phase containing aliovalent ions. The lattice parameter “ $a$ ” of synthetic garnets decreases linearly with Ce concentration. From the static magnetic measurements, we observed that the saturation magnetization $(4\pi M_{S})$ decreases due to combined effect of Ce3+ paramagnetic ions and Ce4+ diamagnetic aliovalent ions. Magnetization dynamics have been studied by ferromagnetic resonance (FMR) technique in flip-chip geometry on the coplanar waveguide. Field sweep FMR spectra revealed that the microwave absorption in the $X$ -band and the Ku-band decreases with Ce concentration due to a decrease in the super-exchange interaction between Fe ions at [a] and (d) sites due to electronic transition of Ce3+ ion. A major investigation of this study shows a decrease in the Gilbert damping constant ($\alpha $) from $1.6\times {10}^{-3}$ to $1.52\times {10}^{-3}$ and increase in extrinsic contribution $\Delta ({H}_{O})$ to the FMR linewidth $\Delta {(H)}$ from 0.38 to 0.54 kOe with Ce concentration. Therefore, this investigation opens a door for the next generation magneto-electric, magneto-optic, and magneto-dielectric effect-based spintronics/magnonics devices in the microwave regime. [ABSTRACT FROM AUTHOR]

The ultrafast manipulation of spin in ferromagnet-semiconductor (FM/SC) heterojunctions is a key issue for advancing spintronics, where magnetic damping and interfacial spin transport often define device efficiency. Leveraging selective optical excitation in semiconductors offers a unique approach to spin manipulation in FM/SC heterojunctions. Herein, we investigated the magnetic dynamics of a Co 2 FeAl/ n -GaAs heterojunction using the time-resolved magneto-optical Kerr technique and observed the considerably enhanced magnetic damping of Co 2 FeAl when GaAs is photoexcited near its band edge. This enhancement is attributed to an enhanced spin-pumping effect facilitated by spin-dependent carrier tunneling and capture within the Co 2 FeAl layer. Moreover, circularly polarized light excites spin-polarized band-edge photocarriers, further impacting the magnetic damping of Co 2 FeAl through an additional optical spin-transfer torque on the magnetic moment of Co 2 FeAl. Our results provide a valuable reference for manipulating spin-pumping and interfacial spin transport in FM/SC heterojunctions, showcasing the advantage of optical control of semiconductor photocarriers for the ultrafast manipulation of magnetic dynamics and interfacial spin transfer.

The static and dynamic magnetization response of the CoFeB/IrMn/CoFeB trilayer system with varying thickness of the antiferromagnetic (AF) IrMn layer is investigated using magnetization hysteresis (M–H) and ferromagnetic resonance (FMR) measurements. The study shows that the two CoFeB layers are coupled via a long-range dynamic exchange effect through the IrMn layer up to a thickness of 6 nm. It is found that with the increase in IrMn layer thickness a nearly linear enhancement of the effective magnetic damping constant occurs, which is associated with the simultaneous influence of spin pumping and interlayer exchange coupling effects. An extrinsic contribution to the linewidth originating from the two-magnon scattering is also discussed. The AF-induced interfacial damping parameter is derived by studying the evolution of damping with inverse CoFeB thickness. The static magnetic measurements also reveal the interlayer exchange coupling across the IrMn layer both at room temperature and low temperature. The asymmetric hysteresis loop and training effect observed at low temperature is related to the presence of a metastable AF domain state. We show that both the static and dynamic magnetic properties of trilayer films can be adjusted over a wide range by changing the thickness of the IrMn spacer layer.

In this paper, details of the design work for a tuned vibration absorber to be used on a hollow cylindrical structure is presented. The vibration problem is of resonant type and the tuned vibration absorber is designed to suppress the displacement vibration response of the free end of the slender hollow structure dominated by the contribution of its lowest transverse vibration modes. The structure is modeled using a commercial finite element software. Finite element model of the structure is verified using experimentally obtained frequency response functions and modal parameters. Effective parameters of the tuned vibration absorber design are then determined based on finite element analysis simulations of the vibration suppression performance of the tuned vibration absorber as it is used on the structure. Details of the tuned vibration absorber design are determined and a prototype is fabricated. Prototype tuned vibration absorber is then characterized experimentally both as a standalone system and also as it is used on the main structure. Vibration reduction performance of the physical prototype of the tuned vibration absorber is also compared with its vibration reduction performance estimated from finite element analysis simulations so that the analysis based design process can be validated. Communicated by Dumitru Caruntu. [ABSTRACT FROM AUTHOR]

[Display omitted] • The magnetic relaxation of CrO 2 film is significantly enhanced by the antiferromagnetic RuO 2 layer. • The magnetic damping of CrO 2 film can be strongly modulated via the interfacial effect from the neighboring RuO 2 layer. • The CrO 2 films epitaxially grown on RuO 2 layer exhibit a perfect in-plane magnetic uniaxial anisotropy. • Intergrain tunnelling magnetoresistance and double-exchange mechanism leads to a linear magnetoresistance in CrO 2 film. Half-metallic chromium dioxide (CrO 2) is a promising candidate in magnetic random-access memory (MRAM) devices due to its nearly full spin polarization and ultralow Gilbert damping at room temperature. In this study, we succeeded in fabricating (1 1 0) and (1 0 0)-oriented RuO 2 /CrO 2 bilayers with different thicknesses of CrO 2 film using two-step method. The CrO 2 film epitaxially grown on a RuO 2 layer exhibits a perfect in-plane magnetic uniaxial anisotropy. The magnetic relaxation of CrO 2 films can be strongly modulated via the proximity to RuO 2 layer, which may relate to the enhancement of the two-magnon scattering due to effects of antiferromagnetic order in RuO 2 film. In addition, electronic transport measurements indicate that the electronic characteristic is strongly related to the film growth orientation, and a linear magnetoresistance is observed stemming from intergrain tunneling magnetoresistance and double-exchange mechanism. Angle-dependent ferromagnetic resonance measurements indicates that the uniaxial anisotropy in CrO 2 film is strongly related to the strain effect, which is consistent with reciprocal space mapping results. This work lays a foundation for current-drive MRAM based on RuO 2 /CrO 2 bilayer and provides a feasible damping modulation method for CrO 2 film. [ABSTRACT FROM AUTHOR]

Purpose of this paper is to reduce the response of rocking vibration mode of vertically isolated equipment. The rocking vibration is the motion that the top of equipment vibrates as the fulcrum in a bottom end. According to the low vertical stiffness of vertically isolated equipment, the rocking vibration is largely excited by horizontal earthquake motion. In this paper, a dynamic absorber is developed in order to apply to the rocking vibration of the vertically isolated equipment. The proposed system is a rolling pendulum type dynamic absorber using magnetic damper, which is composed of circular rails, a rolling body including magnets and a conductor plate. The design method for the dynamic absorber and the evaluation method for vibration reduction effect are showed in this paper. The dynamic characteristics are also examined by vibration test. It is confirmed from the vibration tests using a rocking model apparatus that the proposed dynamic absorber is effective for rocking vibration reduction.

Rapid manipulation of magnetization orientation by a femtosecond pulse laser is an efficient way for advanced information storage technology. We report a comprehensive study of the interlayer coupling effect on the magnetization dynamics in [Ni/Co]4/Ru-(tRu)/[Co/Ni]3 perpendicular magnetic films by the time-resolved magneto-optical Kerr effect approach. By controlling the antiferromagnetic (AF) interlayer coupling field H ex and external magnetic field H, we demonstrate distinctly different dynamic behaviors upon laser excitation. First, three kinds of demagnetization process, including nonchange, ultrafast increase, or decrease in Kerr signal, can occur within the short time delay of 2 ps. Second, in the relaxation process, in addition to the normal coherent precession, an additional out-of-phase mode is detected for the AF-coupled samples, whose amplitude and frequency depend also strongly on H ex and H. The H-dependent frequency curves of both modes are well interpreted with the deduced analytical expression by taking the bilinear and biquadratic coupling into account. Additionally, the magnetic damping of optical mode not only is coupling-dependent but also shows a strong peak at a critical field H crit, which is found to scale with H ex. These results provide new insights into the magnetic dynamics in perpendicularly exchange-coupled systems for spintronic applications with ultrafast control of information operation. [ABSTRACT FROM AUTHOR]

The pump fluence- and amplitude of magnetic field-dependent demagnetization and dynamic processes are well studied in the Co 2 FeAl(CFA) films prepared on the MgO substrates at different temperatures by the time resolved magneto-optical Kerr effect (TR-MOKE). It is found that the demagnetization and the damping processes are strongly dependent on both the amplitude of the external fields and the pump fluences in low fields, resulting in a complex spin relaxation and damping behavior, which is mainly attributed to the non-uniform precession mode induced by the inhomogeneous magnetic anisotropy distribution and the anisotropy field competition. However, with increasing magnetic field gradually, the demagnetization and dynamic processes start to be dominated by the external field, and meanwhile the uniform spin-wave arises. More importantly, the dynamic properties are nearly independent of the amplitude of the magnetic fields and the pump fluences again. The constant damping parameter, which decreases slightly from 4.02 × 10−3 to 1.55 × 10−3 with grown temperature changing from 300 °C to 700 °C, is suggested to be an intrinsic characteristic of the CFA films, and can be attributed to the improvement of the atomic ordering and the crystal quality. • Dynamic processes of CFA are strongly dependent on pump power in low fields. • Dynamic properties are independent of pump power in high fields. • Intrinsic dynamic properties are different for CFA films grown from 300 °C to 700 °C. • Damping parameter decreases slightly from 4.02 × 10−3 to 1.55 × 10−3 for different CFA films. [ABSTRACT FROM AUTHOR]

Abstract This paper presents a magnetic means of accumulating kinetic energy from a traversing rod (TR) used to guide yarn during winding processes on rotor spinning machines. A passive magnetic system for accumulating kinetic energy at the reversal points of reciprocating motion is introduced, and its unique repulsive magnetic force is described in relation to the specific traversing-motion characteristic. The magnetic damping force phenomenon and preconditions for its application in the machine are also defined and discussed. We also show magnetic field optimisation by means of pole-piece geometry modification to obtain a magnetic force characteristic that closely approximates the required motion characteristic. Thus, the efficiency of kinetic-energy accumulation at the reversal points of the reciprocating motion of the TR is increased. The utilisation of an eddy-current effect on the accumulator body to apply the magnetic-damping phenomenon for vibration reduction is also described. The results of this work demonstrate the promise of the system using modern rare-earth compound-based magnets applicable not only to the studied traversing system but also to various mechanical devices as a non-contact means of reducing deformation and vibration. The developed and experimentally verified mathematical models presented here represent a useful tool for further optimisation of specific applications in the field of mechanics. Graphical abstract Image 1 Highlights • The unique peak-like magnetic repulsive force-distance characteristic of a passive magnetic system. • Passive magnetic system reduces considerably deformation and vibration of the rectilinear-motion based mechanical system. • FEM based models of magnetic systems were experimentally verified with satisfied correspondence. [ABSTRACT FROM AUTHOR]

Abstract The ferromagnetic insulators (FMI) involving the phonon-magnon interaction in generation of spin currents are providing new opportunities to explore the thermal to electrical conversion efficiency in comparison to electron based themoelectrics. Here, we have investigated the magnetic damping behavior and spin Seebeck effect in crystalline, highly smooth surfaced, nano-meter thick FMI Ce 0.5 Y 2.5 Fe 5 O 12 (CeYIG) films, synthesized via pulsed laser deposition technique, for their application in spin caloritronics. The CeYIG films reveal an increase of saturation magnetization, strong magnetic anisotropy and a very low magnetic damping, optimum for investigation of pure spin currents generated via inverse spin Hall Effect. The room temperature longitudinal spin Seebeck effect (LSSE) was observed on sputtering of 8 nm thick Hall bar patterned rhodium (Rh) on CeYIG films. The magnitude of LSSE voltage obtained showed a characteristic increase and saturation of signal with the increase of film thickness, indicating the origin of spin current generation from the bulk of CeYIG film. The pure spin Hall magnetoresistance (SMR) was observed in temperature range of 5–300 K implying the LSSE observed in Rh layer is purely from the spin current generated within the FMI and free from parasitic magnetic proximity effect (MPE). The use of Rh as a normal metal for the detection of spin current can open a new window in the exploration of pure spin current related phenomena. Highlights • Crystalline nano-films of Ce doped Yttrium iron garnet deposited via pulsed laser deposition technique. • A very low magnetic damping is observed even on Ce doping. • The CeYIG films exhibit increase in saturation magnetization, strong magnetic anisotropy and enhanced Kerr rotation. • Observation of room temperature longitudinal spin Seebeck effect (LSSE) with a clear SMR signal down to 5 K. • A characteristic increase and saturation of LSSE signal with film thickness [ABSTRACT FROM AUTHOR]

Abstract Rhodium (Rh) is a 4d metal possessing a large spin orbit coupling strength and spin-Hall conductivity with a very small magnetic susceptibility, implying an insignificant magnetic proximity effect (MPE). We report here the observation of longitudinal spin Seebeck effect (LSSE) using Rh as a normal metal. A Rh film was sputtered on nanometer thick YIG films of highly crystalline nature and extremely low magnetic damping to obtain Rh/YIG hybrid structure. A clear thermal voltage V th (SSE voltage) was obtained when a temperature gradient was applied on the Rh/YIG hybrid. The Rh film showed a very weak anomalous Hall resistance and the magneto-resistive testing clearly ruled out the magnetization of the Rh films via MPE. The anisotropic magnetoresistance (AMR) revealed a clear spin hall magnetoresistance (SMR) signal in Rh film implying a purely intrinsic spin current generation, free from any parasitic magnetic effects. The work can open a new window in the study of pure and uncontaminated spin current, generated in ferromagnetic insulators, using Rh as spin current detector. Highlights • Synthesis of highly crystalline nanometer thick YIG films with very low magnetic damping. • Observation of room temperature longitudinal spin Seebeck effect using Rh as a spin detector. • Magneto-resistive measurements clearly ruling out the magnetization of Rh films via magnetic proximity effect. [ABSTRACT FROM AUTHOR]

Abstract We present here the magneto thermal properties, damping behavior and effect of Cerium doping on ferromagnetic insulator Yttrium Iron Garnet (YIG), synthesized via solid state method and Spark Plasma Sintering. The thermal conductivity was measured using Laser Flash technique in the temperature range of 300–1000° K. A decrease in thermal conductivity was observed up to the Curie temperature of YIG, beyond which it showed a constant behavior. On Ce doping of YIG, 15% enhancement of thermal conductivity was achieved, besides leading to an increase of magnetic moment at all temperatures. This gain is attributed to the increase of grain size and replacement of diamagnetic Y3+ ions in YIG by paramagnetic Ce3+ ions in Ce doped YIG. The spark plasma sintered YIG showed a decrease in particle size and grain size resulting in decrease of both thermal conductivity and saturation magnetization. The damping parameters obtained from ferromagnetic resonance measurement revealed a very low magnetic damping even on Ce doping. The work provides effective information regarding the enhancement of spin dynamic properties of YIG suitable for spin-caloritronic applications. [ABSTRACT FROM AUTHOR]

Highlights • General approach for magnetic dissipative effects from dynamical lattice. • Molecular-spin dynamics with full conservation of angular momentum. • Non-exponential magnetic relaxation behavior for excited lattice dynamics. Abstract A combined dynamics for the spin and lattice degrees of freedom is proposed. For that we couple a Heisenberg spin Hamiltonian via a distance dependent exchange integral and an anisotropic correction to the lattice, where the latter is formed by a harmonic potential. With these extensions the transfer of energy as well as angular momentum between lattice and spins is possible. We test this model successfully by reproducing the Einstein-De Haas effect for a free cluster. On the other hand we find severe differences of the temperature dependent demagnetization dynamics of the new approach as compared to the well-established magnetization dynamics covered by Gilbert damping. [ABSTRACT FROM AUTHOR]

Abstract In this paper, we present the electromechanical coupled analysis of the ITER vacuum vessel in case of slow downward locked and rotating Asymmetric VDEs. The numerical model for simulating the AVDE includes the asymmetric distribution of the halo currents obtained by a suitable 3D kink perturbation of a slow VDE downward computed by the 2D code DINA. In the case of a rotational AVDE, the rotation frequency of the kink asymmetry has been chosen to be ω = 2π × 5 rad/s. The model includes the mesh of the main passive components facing the plasma. The whole torus (360 degrees) has been discretized. It is shown that the very high complexity of the numerical model can be suitably treated. The strength of the sideways force here computed is comparable with previous estimates. The damping effect due to the interaction with the external field is evaluated showing a positive mitigation of the mechanical oscillations of the vessel during the electromagnetic transients [ABSTRACT FROM AUTHOR]

The crystallization of CoFeB electrode is essential for achieving high tunneling magnetoresistance (TMR) in magnetic tunnel junctions (MTJs) with MgO barrier. In this study, we systematically investigated the influence of annealing on the structural and magnetic properties of CoFeB (23 nm) thin films using X-ray diffraction (XRD), magnetization ( M ) vs. magnetic field ( H ) and ferromagnetic resonance (FMR) measurements. The variations in composition and uniaxial magnetic anisotropy (UMA) of as-deposited CoFeB thin films results in a different crystalline state on annealing. It was found that the partial crystallization takes place for CoFeB compositions with high Boron content and exhibiting large UMA. This initial stage of crystallization is associated with the quick release of stress and will result in low coercivity, smaller crystallite size and a decrease in uniaxial anisotropy which will eventually lead to lower magnetic damping. However, on complete crystallization for other compositions with the formation of bcc-CoFe (110) phase, both the crystallite size and coercivity increases and cubic anisotropy emerge which results in very enhanced damping. The FMR linewidth has non-linear frequency dependence which gives direct evidence that relaxation is not exclusively governed by Gilbert damping, but it is also important to consider the contribution from two-magnon scattering (TMS). The TMS dominates the damping process in crystallized films and is mainly caused by the anisotropy dispersion created due to the grain growth. Thus, the work connects the change in microstructure and anisotropy to the magnetization dynamics, in particular, the FMR linewidth. [ABSTRACT FROM AUTHOR]

A description is made of a newly developed base isolation system that in a simple and cost-effective way may significantly reduce the lateral forces transmitted to buildings, bridges and other structures during earthquakes. The system operates on the basis of (a) sliding bearings that incorporate a hydrostatic scheme to minimise the friction between bearings and base plates, and (b) the generation through the use of modern rare earth permanent magnets of damping forces to reduce the bearings’ displacements to practical levels and counteracting forces to push the bearings back toward their initial positions if displaced. The sliding bearings are fabricated with steel tubes, steel cap plates, a low-viscosity fluid, sealing elastomeric O-rings and rare earth permanent magnets attached to the steel tubes. The isolation system is comprised of these bearings, aluminium base plates and rare earth permanent magnets connected to the periphery of these plates. Presented also is a study conducted with a six-storey building to examine the feasibility and practicality of the proposed system. As conceptualised and based on the results from the feasibility study, it is concluded that the suggested isolation scheme is feasible, effective and easy to build and install. [ABSTRACT FROM AUTHOR]

By inserting a Gd layer with strong oxygen-affinitive property, the effect of interfacial oxygen migration on the perpendicular magnetic anisotropy (PMA) and damping constant was investigated in perpendicular Ta/CoFeB/Gd/MgO/Ta multilayers. The overoxidation of CoFeB was greatly suppressed by inserting a thin Gd layer at CoFeB/MgO interface, leading to an O-poor status at interface. Different oxygen migration behavior in samples without and with Gd was observed during the thermal annealing. By optimizing Gd thickness, the effective damping constant of 0.029 and 0.037 was obtained with 0.6 nm Gd layer in out-of-plane and in-plane configuration, respectively. This value was decreased by 70% and 46% with respect to that without Gd layer. More importantly, the PMA can be well maintained when Gd thickness was increased to 1.2 nm. This effective modification of magnetic properties based on oxygen migration provides a promising pathway for spintronic applications. [ABSTRACT FROM AUTHOR]

A new method for analyzing magnetization dynamics in spin textures under the influence of fast electron injection from topological ferromagnetic sources such as Dirac half metals has been proposed. These electrons, traveling at a velocity v with a non-negligible value ofv/c(where c is the speed of light), generate a non-equilibrium magnetization density in the spin-texture region, which is related to an electric dipole moment via relativistic interactions. When this resulting dipole moment interacts with gauge fields in the spin-texture region, an effective field is created that produces spin torques. These torques, like spin-orbit torques that occur when electrons are injected from a heavy metal into a ferromagnet, can display both damping-like and anti-damping-like properties. Finally, we demonstrate that such an interaction between the dipole moment and the gauge field introduces an anomalous velocity that can contribute to transverse electrical conductivity in the spin texture in a way comparable to the topological Hall effect., (© 2023 IOP Publishing Ltd.)

A magnetic damper composed of a permanent magnet and a conducing plate has the advantage that the magnetic damper can generate a damping force with no physically contact. The conducting plate needs to be thickened in order to obtain a stronger magnetic damping force, since the magnitude of the magnetic flux produced by a permanent magnet is limited. However, it is known that the magnitude of the magnetic damping force is limited, even if the conducting plate of the magnetic damper has a large thickness. It has been considered that skin effect by eddy currents is the cause of this limited magnetic damping force. In addition, it is known that eddy currents have a very slight effect on the natural frequency of a structure with a magnetic damper. In this paper, the coil method considering inductances is proposed as one of the modeling methods for magnetic dampers consisting of a ring magnet and a conducting disk moving relatively in an axial direction. Applying this method, a modal analysis of the free and the forced vibration of a 1-DOF system with a magnetic damper are performed, and the magnetic damping and the magnetic stiffness considering the skin effect, are introduced. Furthermore, the experiments are performed in order to confirm the practicality of the method. The analytical results are found to be in agreement with the experimental results.