Properties Of Ribbons Research Articles

Resonance Properties and Magnetic Anisotropy of Nanocrystalline Fe73Cu1Nb3Si16B7 Alloy

Resonance properties of nanocrystalline ribbons of Fe73Cu1Nb3Si16B7 alloy annealed with the use of an electric current under a tensile stress of 180 MPa have been studied within the ferromagnetic resonance method. Two kinds of ferromagnetic regions with different anisotropic behaviors that coexist in the alloy after the annealing are detected. One of them is amorphous and weakly magnetically anisotropic, whereas the other is characterized by a pronounced uniaxial magnetic anisotropy and corresponds to the nanocrystalline phase. Quantitative estimations of magnetic parameters in two magnetic phases of the alloy are made.

Structure and magnetic properties of melt-spun ribbons of Sm(Co,Fe,Cu,Zr)z with high cobalt content

In this work the investigation of structure and magnetic properties of SmCo7.5Fe3.09Cu0.84Zr0.3 and SmCo7.52Fe3.01Cu0.84Zr0.28 melt-spun ribbons with high cobalt content after different heat treatments was performed. The phase composition and magnetic properties of the samples were determined. Isothermal aging at 600-800 °C with subsequent slow cooling leads to the slight increase in coercivity of the samples. After arc-melting the phase composition of the samples is hexagonal Sm2Co17 and CoFe. After melt-spinning a small amount of the disordered SmCo7 phase is detected. After aging metastable SmCo7 disappears, and the phase structure is basically hexagonal phase Sm2Co17 and CoFe, except a tiny amount of SmCo5 and rhombohedral Sm2Co17 after aging at 800 °C. Magnetic properties of the samples are relatively low because the phases, essential for the high-coercive state in these alloys, do not form during applied heat treatments.

Effect of heat treatment process on the structural and soft magnetic properties of Fe38Co38Mo8B15Cu ribbons

In this study, the effect of crystal formation, grain growth and surface properties on magnetic properties via changed with heat treatment process in amorphous Hitperm-type alloy produced by planar flow casting method was investigated. The produced Fe38Co38Mo8B15Cu1 amorphous ribbons were subjected to selected heat treatments. The low temperature and short time heat-treated samples displayed broad, continuous, and low-intensity XRD diffraction peaks and the intensities of the crystalline peaks increased noticeably with increasing time and temperature. The AFM images of as-quenched Fe38Co38Mo8B15Cu1 ribbon surfaces displayed one type of sharp peak raises evenly distributed on the surfaces. The microstructural of the heat-treated samples exhibited nanocrystalline bcc-FeCo grains randomly dispersed in the remaining amorphous matrix. The mean sizes of grains increased from 1.8 nm to 5.6 nm with increasing heat-treatment temperature and time. The saturation magnetization increased from 81 to 135 emu/g with increasing heat-treatment temperature ranging from 300 to 420 °C and then decreased to 113 emu/g for 450 °C. The coercivity showed the or non-monotonous dependence with increasing annealing time and temperature.

Assessment of dynamic properties of hybrid ribbon reinforced multifunctional composite sandwich plates: Numerical and experimental investigation

Abstract This study investigates numerically and experimentally the effect of longitudinal ribbon reinforcement in conventional honeycomb structure on the various dynamic characteristics of a hybrid composite sandwich plate. Longitudinal strips are considered to be embedded along the transverse directions at various locations of a honeycomb core material without and with carbon nanotubes (CNT) reinforcement in a composite sandwich plate. The governing differential equations of motion of the various hybrid honeycomb composite sandwich plate configurations with strips inserted in conventional honeycomb structures as core layer having top and bottom face composite layers are derived using higher order shear deformation theory (HSDT) and solved numerically using a four noded rectangular finite element. Further, experimental investigations are performed by fabricating the various strips embedded hybrid honeycomb core material with and without CNT reinforcement to evaluate the shear and loss moduli using the alternative dynamic approach. The efficacy of the developed finite element formulation is demonstrated by comparing the experimental and numerical results obtained in terms of natural frequencies and loss factors for the various prototypes of honeycomb composite sandwich plates. Also, the effect of variation in CNT content and thickness of longitudinal ribbon reinforcement in conventional honeycomb core material and ply orientation of the face sheets on the various dynamic properties of hybrid composite structures are studied under various end conditions. This study proposes that the ribbon reinforcement location and the addition of CNTs in honeycomb core materials strongly influence the stiffness, damping and transverse vibration displacements of the ribbon reinforced hybrid composite sandwich plates.

Electronic and transport properties and physical field coupling effects for net-Y nanoribbons

Recently, a new type of quasi-1D graphene-like nanoribbons, periodically embedded with four- and eight- membered rings, has been successfully fabricated, and based on this structure, a novel planar 2D carbon allotrope, the so-called the net-Y, has been proposed. Here, we study various nanoribbons derived from such a 2D monolayer focusing on the structure stability, electronic, and transport properties, especially on the physical field coupling effects of electronic behaviors. Very high stability is predicted for various types of nanoribbons by the calculated binding energy and molecular dynamics simulation. Different edge shapes and widths have a significant influence on their electronic properties. Armchair nanoribbons are always semiconductors, and possess a high carrier mobility. After hydrogen termination, some metallic nanoribbons can become semiconductors or quasi-metals with massless Dirac-fermion behavior. In particular, the electronic properties of ribbons can be effectively modulated by applying strain and electric field. The band gap size and the transition from indirect to direct band gap can be realized upon strain or electric field. These flexibly tunable electronic properties for nanoribbons expand their applications in nanoelectronics and optoelectronics.

Precipitation hardening by nanoscale Ti2Ni phase in high Ti-rich Ti52.6Ni46.8Si0.6 melt-spun ribbon

A high Ti-rich Ti52.6Ni46.8Si0.6 ribbon was investigated to reveal the precipitation hardening effect caused by the nano-scale Ti2Ni precipitates. TEM observations revealed only nano-scale Ti2Ni second phase in the ribbon after aging treatment, which induced the R phase transformation detected in DSC tests. Nanoindentation measurements demonstrated the increment of hardness from 2.43 GPa to 2.98 GPa, an increment of about 22%, in the first 3 h of aging treatment at 500 °C. The pseudoelasticity (PE) of the ribbon, evaluated by depth and energy recovery ratios of nanoindentation tests, also revealed that 3 h-aged ribbon had the best recovery performance. The shape memory effect (SME) of the 3 h-aged ribbon exhibited the best performance with a recoverable strain of 3.5% and an irrecoverable strain smaller than 0.1%. Both PE and SME tests demonstrated that the precipitation hardening effect of nano-scale Ti2Ni precipitates can effectively improve the shape memory properties of high Ti-rich TiNi shape memory ribbons.

Surface and structural characterization of amorphous Fe,Co-based melt-spun ribbons subjected to heat treatment processes

In this paper, the effect of the heat treatment process on the surface morphology, crystallization process and magnetic properties of Fe38Co38Mo8B15Cu ribbons produced by melt spinning was investigated. Number of protrusions uniformly distributed on surfaces of as-quenched ribbons were identified by atomic force microscopy (AFM). AFM results also indicated that variation of surface morphology of density, size, and shape of protrusions along the ribbon surface. According to magnetic force microscopy (MFM) analysis, the magnetic domain walls were not observed for annealing temperatures of 300 °C–360 °C. After annealing at 420 °C, the domains grow wider and align parallel to each other. Minor amounts of bcc-FeCo nano-sized crystalline grains which homogeneously and randomly distributed to the residual amorphous matrix were observed by the transmission electron microscopy (TEM). The crystalline grains are enlarged and became more visible. The best coercivity and saturation magnetization values were obtained at 360–420 °C.

Tunable plasmonic properties of graphene ribbon for hypersensitive nanosensing

Plasmonic sensing based on symmetrical and asymmetrical graphene metamaterials at the infrared region are proposed and investigated numerically by using three dimensional finite-difference time-domain (FDTD) method. The simple unit cell structure is composed of two parallel graphene ribbons and Al2O3 strips. It is shown that transmission resonance dip shifts can be achieved with a variation of the chemical potential of the graphene ribbon.The sensitivity of the proposed metamaterial is also calculated. Our simulations reveal that, by modulating the chemical potential from 0.8 eV to 0.5 eV, a single layer asymmetrical graphene ribbon can achieve a sensitivity of 6500 nm/RIU, compared to 5725 nm/RIU for double layer asymmetrical graphene ribbons. The finding will pave the way towards graphene based tunable devices for sensing in infrared region.

Enhanced reflective dichroism from periodic graphene ribbons via total internal reflection

A rigorous homogenization theory is developed to characterize the effective conductivity tensor of periodic graphene ribbons. This way, the obtained conductivity simplifies the study of the exotic scattering properties of periodic graphene ribbons. As a typical example, we find that the performance of reflective dichroism from the designed graphene ribbons can be enhanced (up to a maximum linear dichroism of 0.98) when the total internal reflection happens. Moreover, by rotating its optical axis, the functionality of the periodic graphene ribbon can change from an absorber for linearly polarized waves to another absorber for circularly polarized waves (maximum circular dichroism of 0.93). The revealed indispensable property of graphene ribbons in controlling the reflective dichroism indicates their promising wide applications including energy harvesting and optical sensing.

The effect of heat treatment on magnetic and thermal properties of Finemet-type ribbons and microwires

Abstract We studied the influence of annealing conditions on magnetic and thermal properties of Finemet-type alloys. The evolution of the Curie temperature, Tc, and the change of heat capacity in the vicinity of this magnetic transformation, ΔCpTc, were investigated using Differential Scanning Calorimetry, DSC. Relaxation of atomic structure of amorphous phase during the annealing was accompanied by an increase in Tc and decrease in ΔCpTc. Two relaxation processes with different mechanisms take place in amorphous state: topological ordering and chemical ordering. The study of the kinetics of relaxation process allows to estimate the apparent values of activation energy of both relaxation processes: 29 and 87 kJ/mol for ribbon, 37 and 112 kJ/mol for microwire. Precipitation of α-Fe nanocrystallites in amorphous phase leads to gradual degradation of the Tc peak. The Tc peak reduction is correlated to decrease of the amorphous phase as well as lowering of its magnetostriction. The influence of internal stress on the position and shape of the Curie peak was determined by comparing data for the ribbon-shaped alloys and glass coated microwires. Considerable magnetic softening and giant magnetoimpedance effect under heat treatment is observed in the studied Finemet-type microwires. Changes in magnetic properties after heating are associated with devitrification and stresses relaxation. We also study the influence of internal stresses induced by glass coating on the magnetic properties of as-prepared and annealed microwires. The results confirm the previously made conclusion that changes in the thermal and magnetic properties of Finemet-type alloys during heating are interrelated, since they are reflections of the fundamental characteristics of the material.

On-Surface Synthesis and Characterization of Acene-Based Nanoribbons Incorporating Four-Membered Rings.

A bottom up method for the synthesis of unique tetracene-based nanoribbons, which incorporate cyclobutadiene moieties as linkers between the acene segments, is reported. These structures were achieved through the formal [2+2] cycloaddition reaction of ortho-functionalized tetracene precursor monomers. The formation mechanism and the electronic and magnetic properties of these nanoribbons were comprehensively studied by means of a multitechnique approach. Ultra-high vacuum scanning tunneling microscopy showed the occurrence of metal-coordinated nanostructures at room temperature and their evolution into nanoribbons through formal [2+2] cycloaddition at 475 K. Frequency-shift non-contact atomic force microscopy images clearly proved the presence of bridging cyclobutadiene moieties upon covalent coupling of activated tetracene molecules. Insight into the electronic and vibrational properties of the so-formed ribbons was obtained by scanning tunneling microscopy, Raman spectroscopy, and theoretical calculations. Magnetic properties were addressed from a computational point of view, allowing us to propose promising candidates to magnetic acene-based ribbons incorporating four-membered rings. The reported findings will increase the understanding and availability of new graphene-based nanoribbons with high potential in future spintronics.

Introducing and investigating structural and magnetic properties of ribbons Co68.5-xFe4WxSi16.5B11 (x = 0.8, 2) in amorphous and crystalline states

Introducing and investigating structural and magnetic properties of ribbons Co68.5-xFe4WxSi16.5B11 (x = 0.8, 2) in amorphous and crystalline states

Mechanical and Electromagnetic Shielding Properties of Amorphous FeSiB Ribbon–Reinforced Gypsum Composite Board

AbstractGypsum-based composite boards reinforced with mono- and multilayer perforated amorphous Fe78Si9B13 ribbons were fabricated by pouring gypsum slurry directly into molds with prelaid epoxy-re...

Influence of the surface properties of the connector material on the reliable and reproducible contacting of battery cells with a laser beam welding process

The increasing electrification of the automotive industry leads to a growing demand for high-performance energy storage systems. Three different cell types are used for the construction and production of battery modules or packs. These include, for example 18650 round cells, prismatic cells or pouch cells. For the electrical interconnection of prismatic energy storage devices or round cells, the laser bonding method can be used as a particularly flexible connection technology. This method combines the technique of a conventional wire bonder with laser beam welding. Compared to wire bonding, wider and thicker connectors can be contacted, and thus higher currents can be transmitted. During the production of wires/ribbons for wire bonding, sometimes complicated and costly process steps are necessary in order to ensure a consistently high quality of the produced material and consequently obtain a reproducible wire bonding process. Unfortunately, a polished and hence highly reflective surface of an aluminium or copper ribbon adversely affects the reliability of the laser beam welding process. A rough or oxidised ribbon surface however can favour the coupling of the laser radiation into the copper material and thus contribute to a stable process sequence. In this work, the influence of the surface properties of pure copper ribbons regarding the process reliability is investigated. Therefore, ribbons produced for a wire bonding process are thermally oxidised or mechanically roughened, and their optical properties are compared with a polished reference material. The sample ribbons are welded with a continuous wave fibre laser, and the mechanical properties of the resulting connection are investigated. Due to a more stable interaction of the laser radiation, a mechanically and electrically improved connection is expected.

Development of high-coercivity state in melt-spun Fe41Pd41B8Si6P4 ribbons

The phase transformation and magnetic hysteresis properties of melt-spun Fe41Pd41B8Si6P4 ribbons subjected to the annealing at temperatures of 500–550 °C were studied after holding for 0.1–60.0 h by transmission electron microscopy (TEM), X-ray diffraction (XRD) and thermomagnetic analysis. The additions of P, B and Si to the FePd alloy allowed us to achieve the coercivity of 124 kA·m−1, which is 2.6 times higher than that of the melt-spun ribbons of the binary equiatomic FePd alloy. The high-coercivity Fe41Pd41B8Si6P4 alloy is nanocrystalline and is composed of the ordered L10-phase grains approximately 40 nm in size and inclusions of the Fe2(P, B) and Pd2(Si, B) phases. The coercivity kinetics is controlled by the phase transformation which can be divided into three stages: transformation from the bcc structure to nanosized regions of the fcc and Fe2P phases; transformation from the fcc to L10 nanosized regions with somewhat different degrees of tetragonality and their ordering; and extensive growth of the weight fraction of L10 phase from the fcc nanosized regions. P and B atoms occupy interstitial sites in the iron plane of L10 lattice, thus decreasing its Curie temperature (TC).

Electronic properties of atomic ribbons with spin-orbit couplings on different substrates

Atomic ribbons and monoatomic chains on different substrates are proposed as spin-dependent electrical conductors with asymmetrical local density of states (DOS) and ferromagnetic occupancies along the chains. The tight-binding Hamiltonian and Green’s function techniques were used to analyze the electrical properties of both normal and topological systems with spin-orbit scattering. To make the system more realistic, electron leakage from atomic chains to various types of substrates is considered. We have shown that delocalized electrons in the substrate and spin-orbit interactions are responsible for asymmetry in the local DOS. The structure of DOS for spin-orbit nontopological chains is spin-dependent at both chain edges; however, in the middle of the chain, only paramagnetic solutions are observed. Additionally, we have found different periods of the local DOS oscillations along the chain in the presence of spin-flip and spin-orbit couplings. For topological chains, the edge nontrivial states split in the presence of spin-orbit scattering and spin-dependent Friedel oscillations appear along the whole topological chain. We have also found out-of-phase Friedel oscillations between neighboring chains along the atomic ribbon.

Significant improvement of soft magnetic properties for Fe-based nanocrystalline alloys by inhibiting surface crystallization via a magnetic field assisted melt-spinning process

Abstract Fe-based soft-magnetic amorphous and nanocrystalline ribbons made with a single-side fast-cooling process always suffer from the surface crystallization which deteriorates the magnetic properties and inhibits the wide applications. In this study, a static magnetic field assisted melt-spinning process was employed to prepare the typical Fe84.75Si2B9P3C0.5Cu0.75 alloy ribbon with an attractive application prospect. According to the comparative investigations of the crystallization behavior, structural evolution process and magnetic properties, it is found that the applied magnetic field can effectively inhibit the formation of compound phases and decrease the size of textured α-Fe grains in the surface layer of the as-spun ribbon. The Fe84.75Si2B9P3C0.5Cu0.75 samples made with low purity raw materials and under an optimal field exhibit superior magnetic properties, including a high saturation magnetization (Bs) over 1.82 T, low coercivity (Hc) of 8.5 A/m, high permeability (μ) of 2.76 × 104 at 1 kHz and much lower losses, after nanocrystallization by annealing. The apparent effect of the applied magnetic field was discussed from the disturbance of a Lorentz force of the fast-moving molten alloy and a magnetic force of preformed grains in a magnetic field during the melt-spinning process. These results provide a novel solution of surface crystallization and an effective route for improving magnetic properties of Fe-based amorphous and nanocrystalline alloy ribbons.

Effect of additions of phosphorous, boron, and silicon on the structure and magnetic properties of the melt-spun FePd ribbons

Abstract Formation of the L10 structure in FePd alloys doped with nonmetallic elements is studied on melt-spun and annealed samples. The melt-spun Fe41Pd41P18−x−yBxSiy (x = 0–14; y = 0, 6) ribbons were annealed at the temperatures of 400–650 °C for different holdings in the range from 5 min to several hours and studied by X-ray and thermomagnetic analysis and TEM. The saturation magnetization, Curie temperature of the L10 phase, and grain size of the melt-spun doped Fe41Pd41P18−x−yBxSiy ribbons decrease in comparison with those of the melt-spun binary FePd alloy. The refined grain structure results in enhancing coercivity. Among all as-annealed samples, the P addition favors the amorphization of the as-spun Fe41Pd41P18 ribbons and refines grains of the formed L10 phase, but decreases magnetization. Substitution of B for P gives rise to magnetization of the Fe41Pd41P18−x−yBx alloys, but decreases their coercivity. A partial substitution of Si for B at the same P content refines grains and enhances the coercivity without a decrease in the magnetization of the Fe41Pd41P4B8Si6 alloy. It is suggested that P and B atoms occupy interstitial sites in the L10 lattice in the iron plane, weakening the exchange interaction and decreasing the Curie temperature. The additions of P, B, and Si to the FePd alloy allowed us to obtain the Fe41Pd41P4B8Si6 ribbons with the coercivity of 1560 Oe, which is 2.6 times higher than that of the melt-spun ribbons of the FePd alloy.

Magnetic and magnetocaloric properties of Pr2-xNdxFe17 ribbons

The structural, magnetic and magnetocaloric properties of Fe deficient Pr2-xNdxFe17 (x = 0.5, 0.7) alloys prepared by arc-melting and melt-spinning have been investigated. The room temperature x-ray diffraction patterns show that the samples are nearly single-phase and crystallize in the rhombohedral Th2Zn17-type crystal structure. The Curie temperatures determined from the thermomagnetic curves are 302 K and 307 K for Pr1.5Nd0.5Fe17 and Pr1.3Nd0.7Fe17, respectively. The peak magnetic entropy change and the relative cooling power at field change of 50 kOe are 3.01 J/kgK and 345 J/kg for Pr1.5Nd0.5Fe17, and 4.31 J/kgK and 487 J/kg for Pr1.3Nd0.7Fe17, respectively. The absence of magnetic and thermal hysteresis with relatively high cooling efficiency suggests that the alloys have potential for magnetic refrigeration.

Transport properties of ferrimagnetic Mn2CoSn Heusler alloy

Abstract Transport properties of bulk samples and melt-spun ribbons of Mn2CoSn alloy were investigated. It was found that Mn2CoSn is a high-resistance compound with the value of electrical resistivity ρ ∼ 300 μOhm·cm at room temperature and demonstrates semiconducting behavior of ρ as a function of temperature. A change in the dominating conductivity type from hole-like to electron-like takes place upon heating above ≈137 K. Abnormal Hall coefficient RS is large and depends on electrical resistivity as RS ∼ ρ2.