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Theodore H. Geballe: Selected Research Papers (1950-2019) D. N. Lyon, T. H. Geballe, The temperature coefficient of resistance of tin oxide-coated electrically conducting glass between 1-degrees-K and 300-degrees-K, I Review of Scientific Instruments i B 21 b , 769-770 (1950). I. Bozovic, D. Kirillov, A. Kapitulnik, K. Char, M. R. Hahn, M. R. Beasley, T. H. Geballe, Y. H. Kim, A. J. Heeger, Optical measurements on oriented thin YBa SB 2 sb Cu SB 3 sb O SB 7- sb films - lack of evidence for excitonic superconductivity, I Physical Review Letters i B 59 b , 2219-2221 (1987). B. Oh, K. Char, A. D. Kent, M. Naito, M. R. Beasley, T. H. Geballe, R. H. Hammond, A. Kapitulnik, J. M. Graybeal, Upper critical-field, fluctuation conductivity, and dimensionality of YBa SB 2 sb Cu SB 3 sb O SB 7-x sb , I Physical Review B i B 37 b , 7861-7864 (1988). J. J. Yeh, I. Lindau, J. Z. Sun, K. Char, N. Missert, A. Kapitulnik, T. H. Geballe, M. R. Beasley, Variation of Cu-O charge-transfer energies in YBa SB 2 sb Cu SB 3 sb O SB 7- sb thin-films studied by photoemission spectroscopy, I Physical Review B i B 42 b , 8044-8048 (1990). [Extracted from the article]

For high-temperature superconducting (HTS) cables carrying substantial currents, the current carrying capacity of a single YBCO tape is limited, and multiple tapes need to be connected in parallel. The current sharing design of parallel YBCO tapes has emerged as a central concern in the HTS cable design. However, various tape parameters, including critical current I c , n-value, and joint resistance, can significantly influence the current distribution in the system. In this paper, the influence of YBCO tape parameters on the current distribution characteristics of the cable was studied. The results showed that the current distribution and quench characteristics were regulated by tape I c , tape n-value, and tape joint resistance together, and that meanwhile, the total current also served as an important factor. Significant influence of the joint resistance was also observed in the event of a limited total current, which was no longer obvious for a total current close to the total I c . For the parallel tapes with the same I c , the one with higher resistance quenched later, while in the case of the same resistance, the effect of the tape I c is greater than that of the tape n-value. [ABSTRACT FROM AUTHOR]

The effects of Fe substitution for Ti on the structural and magnetic properties of the (Ti1-xFex)3AlC2(x = 0, 0.025, 0.05, 0.075) MAX phases have been studied. The Fe substitution leads into the expansion along c-axis but shrinkage within ab-plane of the hexagonal unit cell and also the ferromagnetic state at low temperature. The Curie temperature is increased with more Fe substitution. After exfoliation and delamination, their (Ti1-xFex)3C2Tδ 2D MXenes counterparts are obtained with paramagnetic state, which is due to the broken exchange coupling along c-axis resulting from the etching away of Al layer. The best electromagnetic interference properties of − 30 dB within a wide range of frequency with 5.8–26.5 GHz can be achieved in (Ti0.975Fe0.025)3C2Tδ free-standing "paper" made of the corresponding MXene by vacuum-infiltration. [ABSTRACT FROM AUTHOR]

The structural parameters and harmonic conditions detection of superconducting transformer are studied in this paper. And a two-dimensional axisymmetric model of a single-phase 10 kVA HTS transformer is developed using the finite element H-formulation. The study involves determining the optimum structural parameters of the HTS transformer, calculating the AC losses, and analyzing the corresponding trends. In addition, the effect of different distortion currents on the operating state of the HTS transformer under harmonic conditions is investigated. The results show that the primary-secondary winding spacing is negatively correlated with the AC losses. In addition, the influence of harmonic conditions on AC losses mainly depends on the amplitude of the input current, and the higher the total harmonic distortion, the more serious the current waveform distortion, the more likely to produce a temperature surge, thus affecting the operational stability of superconducting transformers. The research results in this paper can provide a reference for the design and operational stability of HTS transformers. [ABSTRACT FROM AUTHOR]

The high-temperature superconducting (HTS) bulks onboard maglev are one of the most promising transportations. In practice, due to the arrangement irregularity of the permanent magnetic guideway (PMG), there is no doubt that the levitation characteristics of HTS bulks will be affected when it runs on it, which is a real-time feedback needed to be studied imminently. On account for this, by using the software COMSOL Multiphysics, this paper, focusing on the real-time feedback of the effect of PMG's irregularity on the HTS bulks' levitation characteristics, establishes a mechanic-electromagnetic-thermal coupling model and proposes a numerical analysis method to study the HTS bulks' levitation characteristics with considering the PMG's irregularity. The results show that the maximum decrease of the average current density of the HTS bulks considering the effect of temperature is about 5% compared with that without considering the effect of temperature, aggravated by the PMG's irregularity. The value of temperature rise inside the HTS bulks changes as unobvious as that at liquid nitrogen part, and the lower part is relatively more pronounced than the other parts. As for the value of temperature rise at the suspension gap, the middle measuring point is obviously higher than the other measuring points. It is worth mentioning that due to the greater effect of PMG's irregularity than the temperature rise, all kinds of data considering the effect of temperature are not always smaller than those without considering the effect of temperature. When without considering the effect of PMG's irregularity, the temperature makes the levitation force with a decrease of 2.3% when the levitation gap is 10 mm and has a certain degree of inhibition on hysteresis. Furthermore, the coupling effect of PMG's irregularity causes the interaction between the guidance force and the levitation force. This study makes a better, accurate, and real-time reflection of the HTS bulks' levitation characteristics, providing an effective reference for the HTS bulks' dynamic analysis. [ABSTRACT FROM AUTHOR]

In this paper, a multi-band acoustic topological insulator based on the Valley Hall effect is designed. Based on the mirror symmetry in the C 3 v point group phononic crystal, by changing the parameters of the primitive cell, the phononic crystal simultaneously has multiple linear Dirac degenerate points at the K point of the Brillouin zone, which can realize multi-band topology valley transmission. The whole triangular multi-band acoustic topological valley insulator system has C 3 v symmetry. By rotating the clover-like scatterer, the mirror symmetry of the structure can be broken, thereby opening the degeneracy at the Dirac point. The energy band is reversed at the K point, realizing the Valley Hall phase transition. By connecting different structural systems, boundary states are constructed to simulate topologically protected edge acoustic transmission. Different phonon crystal structures are further constructed, and their acoustic transmission characteristics are verified by finite element algorithms. This paper can provide guidance for the design and engineering application of multi-band acoustic antennas, acoustic logic control gate circuits, and other functional devices for acoustic communication. [ABSTRACT FROM AUTHOR]

Transport loss is an integral part of high-temperature superconductor (HTS)-coated conductors (CC)'s loss. In the field of high-speed motor, the frequency of the current carried by HTS CCs used as windings can be up to 1MHz. The dependence of transport loss of HTS CCs on current parameters below 1MHz has been investigated based on the H -formulation model in this paper. It is shown that the transport loss of CCs mainly depends on the loss in HTS components and copper components. There exists a transition frequency, below which the loss in the inner HTS layer accounts for the most significant proportion of total transport loss. Above the transition frequency, the transport loss in the outer copper stabilizer becomes the main component. The current amplitude only affects the magnitude of transport loss but does not affect its change rule. Furthermore, the dependence of transport loss on the current waveform is investigated based on typical winding current waveforms. It is also found that there is a transition frequency. The low-order harmonics of current have a greater impact on the transport loss in the HTS layer below the transition frequency. The obtained results of this paper can provide a reference for the research of high-speed superconducting motor and other superconducting equipment in high-frequency current conditions. [ABSTRACT FROM AUTHOR]

High-temperature superconducting (HTS) maglev is a kind of new maglev structure mode. In actual operation, due to the arrangement and assembly error of the magnet of permanent magnet guideway (PMG) as well as the loss and material stripping during operation, superconductive bulks are always in a state of random fluctuation. In order to study the influence of the irregularity of PMG and bridge deflection on the levitation characteristics of superconductors, the model using the E-J power law model is established in COMSOL Multiphysics 5.6, and the random lateral and vertical irregularity coupled with the bridge deflection is added to PMG for research. The results show that the effects of random excitation and bridge deflection on levitation characteristics are coupled and interact with each other. The vertical excitation and bridge deflection affect the guidance force of dewar while the lateral excitation also affects the levitation force. The levitation characteristics of dewar fluctuate with the fluctuation of random excitation. In the condition without excitation and bridge deflection, the levitation force of the dewar used in this paper is maintained at 3.455kN, the guiding force is − 84.987 N, and the average current density is 1.971MA/m2. The levitation characteristics of dewar will fluctuate with the fluctuation of random excitation. When the bridge deflection is added, the levitation force, guidance force, and average current density of dewar will increase with the increase of bridge deflection. Taking the variation of levitation force as an example, the maximum suspension force is maintained near 5.572kN when the bridge deflection is 2 mm, 8.358kN when the bridge deflection is 4 mm, and 11.858kN when the bridge deflection is 6 mm regardless of random excitation. There is a critical point of levitation force when the dewar is suspended on PMG. If the gap between dewar and PMG exceeds the critical point, the average current density will reverse and the levitation force will be negative. The critical point of the model used in this paper is around 21 mm above the PMG. These results provide a reference for the working condition prediction of the HTS Maglev train. [ABSTRACT FROM AUTHOR]

It has been shown that the substrate magnetism of YBCO tapes affects the critical current, but the role of substrate magnetism in the local critical current of the YBCO coils still needs further study. The purpose of this paper is to improve the accuracy of the current numerical model of critical current and to investigate the effect of the substrate layer magnetism on the local critical current of YBCO coils. To improve the accuracy of the present model, the contribution of the self-magnetic field to the anisotropy of the critical current and the reduction of the critical current density near the edge of the tape are considered in the finite element model (FEM). The effect of substrate magnetism on the critical current of YBCO coils is investigated experimentally and numerically, and the mechanism is clarified. It can be found that the critical current obtained by the four-lead method for a multi-turn coil is not the arithmetic average of the critical current per turn. And the magnetic flux density on the surface of coils wound by YBCO tapes with magnetic substrate is much higher than that of coils wound by tapes with non-magnetic substrate, but the magnetic flux density on the YBCO layer inside the tape is smaller. Additionally, the critical current per turn of the coil with magnetic substrate is more uniformly distributed compared with that the coil with non-magnetic substrates. The critical current model of YBCO coils developed in this paper can provide a reference for the design and optimization of HTS devices. [ABSTRACT FROM AUTHOR]

Benefiting from the high critical temperature and high critical current, the second-generation high-temperature superconducting (HTS) tape is widely used in various large-scale magnet applications. Due to the length limitation of producing superconducting tapes, the joints between superconducting tapes are inevitable for large-scale high-field magnets. The joule loss from the joint resistance under over-current conditions is even larger, which will cause a sharp temperature rise, and will also decay the critical current of the superconducting tape. In this paper, 3 configurations of HTS joints are adopted to model the joint resistance characteristics using new methods, whose joint resistance model is coupled with the real-time operating temperature. The results show that the proposed temperature-dependent HTS joint resistance model well matches the experiment and analytical solution. Therefore, both the experiment and novel modeling investigation can provide useful and accurate references for the superconducting joints in real devices, and the temperature-dependent HTS joint resistance model can play an important role in giving early warnings of the over-current for HTS tapes and high-field magnets. [ABSTRACT FROM AUTHOR]

This paper summarises results obtained with stability calculations of thin films and multi-filamentary superconductors. In a series of papers, all the contributions have been published in this journal. We now extend our previous investigations to the temporal aspect of the internal heat transfer and to the material homogeneity problem. Within multi-component heat transfer (solid conduction, radiation), the standard theory of radiative transfer in a coated, thin-film, YBaCuO3 123 superconductor correctly treats the energetic aspects of radiation propagation; this is the actual core of stability models. But a rigorous solution of the temporal aspect still is missing. It is the study of this aspect that would provide a new access to the physics of superconductor stability, in particular if after a disturbance the system is already close to a phase transition. A matrix formulation, using a combination of Monte Carlo and radiative transfer calculations, is suggested to circumvent the temporal solid conduction/radiative transfer problem in multi-component heat flow. As an important result, quench is not an event that proceeds instantaneously. Instead, it is a process the speed of which decreases the more, the closer the superconductor temperature approaches critical temperature until the residual number of electron pairs becomes too small to support critical current. The stability of superconductors and thermal fluctuations might reflect a common background: the relaxation time of the density of electron pairs after disturbances. [ABSTRACT FROM AUTHOR]

The conductor on round core (CORC) cable wound with second-generation high-temperature superconducting (HTS) tapes is a promising cable candidate with superiority in current capacity and mechanical strength. The composing superconductors and the former are tightly assembled, resulting in a strong electro-magnetic interaction between them. Correspondingly, the AC loss is influenced by the cable structure. In this paper, a 3D finite-element model of the CORC cable is first built, and it includes the complex geometry, the angular dependence of critical current and the periodic settings. The modelling is verified by the measurements conducted for the transport loss of a two-layer CORC cable. Subsequently, the simulated results show that the primary transport loss shifts from the former to the superconductors as the current increases. Meanwhile, the loss exhibited in the outer layer is larger than that of the inner layer, which is caused by the shielding effect among layers and the former. This also leads to the current inhomogeneity in CORC cables. In contrast with the two-layer case, the simulated single-layer structure indicates stronger frequency dependence because the eddy current loss in the copper former is always dominant without the cancellation of the opposite-wound layers. The core eddy current of the single structure is denser on the outer surface. Finally, the AC transport losses among a straight HTS tape, a two-layer cable and a single-layer cable are compared. The two-layer structure is confirmed to minimise the loss, meaning an even-numbered arrangement makes better use of the cable space and superconducting materials. Having illustrated the electro-magnetic behaviour inside the CORC cable, this work is an essential reference for the structure design of CORC cables. [ABSTRACT FROM AUTHOR]

In Minkov et al. (Nat. Commun. 13:3194, 2022), Minkov et al. reported magnetization measurements on hydrides under pressure that claimed to find a diamagnetic signal below a critical temperature demonstrating the existence of superconductivity. Here, we present an analysis of raw data recently released (Minkov et al. Nat. Commun. 14:5322, 2023) by the authors of Minkov et al. (Nat. Commun. 13:3194, 2022) that shows that the measured data do not support their claim that the samples exhibit a diamagnetic response indicative of superconductivity. We also point out that Minkov et al. (Nat. Commun. 13:3194, 2022) in its original form omitted essential information that resulted in presentation of a distorted picture of reality, and that important information on transformations performed on measured data remains undisclosed. Our analysis also calls into question the conclusions of Minkov et al.'s trapped flux experiments reported in Minkov et al. (Nat. Phys. 19:1293–1300, 2023) as supporting superconductivity in these materials. This work together with earlier work implies that there is no magnetic evidence for the existence of high temperature superconductivity in hydrides under pressure. [ABSTRACT FROM AUTHOR]

Compared to single-phase multiferroic materials, multiferroic (MF)-magnetoelectric (ME) composites, which combine magnetic and ferroelectric materials, show improved (many orders of magnitude) ME coupling and a higher operating temperature (beyond room temperature). In the present study, lead-free multiferroic Ni0.5Co0.5Fe2O4/BaTiO3 (NCFO/BTO) composites with different weight percentages were prepared through the solid-state reaction approach. The phase purity and structural confirmation were carried out using X-ray diffractograms. The XRD peak shifting in the composites has been observed, and it is attributed to the formation of residual stresses/strains during the sample's grinding, heating, and freezing processes. Fourier-transformative infrared spectroscopy confirmed the presence of metal-oxygen bonds in spinel NCFO and Ti-O and Ba-O bonds in perovskite BaTiO3. UV-vis spectra disclose the energy gap values of the magnetoelectric composites. It has been found that the energy gap values for pure ferrite are 1.53 eV, the pure ferroelectric phase is 2.99 eV, and the composites possess the Eg values of 1.78 eV, 2.33 eV, 2.77 eV with decreasing ferrite concentration. The M-H hysteresis loops reveal the ferromagnetic nature of pure ferrite as well as the presence of ferromagnetism in composites. The magnetic moment of the NCFO has been found as 2.26 µB and it further decreased to 0.59 µB for the 0.25NCFO-0.75BTO compound. The magneto crystalline anisotropy has been calculated using the law of approach (LA) method and the details are discussed in the paper. [ABSTRACT FROM AUTHOR]

Fe-Si-B-Cu-Nb nanocrystalline alloys have been commercially applied at power electronics. However, few research works are focused on improving high-frequency magnetic properties in the alloys. In this paper, the effect of additional magnetic field annealing temperature on high frequency soft magnetic properties of Si-rich FeSiBCuNb nanocrystalline ribbon was investigated. The as-quenched FeSiBCuNb amorphous alloys were crystallized annealing at 550 °C × 60 min for precipitating nanocrystalline α-Fe(Si) phase. Then the crystallized annealed alloy cores carried out additional transverse magnetic field annealing, and the induced uniaxial anisotropy Ku gradually increases from 9.4 to 21.6 J/m3 with increasing the annealing temperatures from 360 to 520 °C. By comparison with the non-magnetic field annealing sample, the μe of nanocrystalline cores with extra field annealing reduces at about the range of 1–30 kHz but gets significant improvement at 50–200 kHz, the Q improves and Ps decrease at all frequencies of 1 ~ 200 kHz. After the magnetic field is annealed at 480 °C, the core achieves optimal high-frequency properties of μe = 37.9 k (f = 100 kHz), Q = 0.87, and Ps = 30.94 W/kg. The improvement of high-frequency properties in cores upon transverse magnetic field annealing can be attributed to the fact that the magnetic domains appear in a rectangular band arrangement and are perpendicular to the longitudinal direction of the ribbon. When the magnetic cores operate in a dynamic magnetization field, the periodic magnetization is mainly characterized by domain rotation. [ABSTRACT FROM AUTHOR]

In this paper, we have investigated the magnetic and magnetocaloric characteristics of a La2MnNiO6 composite, in conjunction with La2MnCoO6. This composite consists of two phases of double perovskite materials. Employing the mean-field approximation, we successfully modeled how magnetization and the change in magnetic entropy vary with temperature under different magnetic fields in our samples. This phenomenological model helped us also plot the maximum magnetic entropy change (-ΔSM)max, full width at half-maximum δTFWHM, and relative cooling power (RCP). Our analysis has revealed an optimal plateau-type magnetocaloric effect near room temperature, corresponding to a specific composition x between 0.2 and 0.5. Ultimately, this theoretical model lets us predict the magnetic and magnetocaloric behavior of composite materials, providing a foundation for future studies. [ABSTRACT FROM AUTHOR]

When calculating the AC loss of REBa2Cu3O7−x (REBCO, RE = rare earth) coated conductor cable with stacked geometry, it is often considered that the tapes in the cable is perfectly stacked (there is no transverse misalignment of the tapes). However, the actual stacked cable will have transverse misalignment. The influence of transverse misalignment of tapes on the AC loss of the whole cable needs to be studied in order to understand the actual situation. In this paper, the 2-D H formulation calculated the AC loss of the cable with 10 tapes stacked in three cases. In the first case, the cables are perfectly stacked without lateral misalignment between the tapes. In the second case, the tapes of the cable are oblique to one side. In the third case, the tapes are disordered with each other. The result shows that under the transport current at 50 Hz, when the transport current is less than 0.75Ic0, the transport loss of the cable with obliquely stacked cable is more than the perfectly stacked cable, and when the transport current is greater than 0.75Ic0, the transport loss of the perfectly stacked cable is slightly larger than the obliquely stacked cable. Moreover, the transport loss of disorderly stacked cable is more than perfectly stacked cable at 50 Hz. When the transport current amplitude and the misalignment distance between the tapes in the cable are constant, the transport loss of obliquely stacked cable and disorderly stacked cable relative to perfectly stacked cable both increases first and then decreases as the frequency increases. Under the 50 Hz magnetization field, the magnetization loss of the perfectly stacked cable is less than the cables with oblique misalignment and disorder misalignment. When the amplitude of the external magnetic field and the misalignment distance between the tapes in the cable are constant, the magnetization loss of obliquely stacked cable and disorderly stacked cable relative to perfectly stacked cable also increased first and then decreased as the frequency increased. [ABSTRACT FROM AUTHOR]

In this survey paper, a complete analysis of the theory and applications of metamaterial (MM) has been delivered. It is proclaimed that MM possesses exceptional properties, due to negative permeability and negative permittivity that are not present in nature. Therefore, they are known as artificial materials. The physical significance is also explained in this paper in the terms of an equivalent circuit model to understand the concept of the MM. This paper also deals with an overview of distinct MM shapes and structures for different applications at different frequencies. Furthermore, the different types of MM-based electromagnetic structures are also incorporated. An overview of the traditional metasurface, single-layered metasurface, and multilayered metasurface structures is also explained with their drawbacks and advantages. In addition, a brief review of 3D, conformal, active, and graphene MM is also included. The different designs are also compared in active, conformal, multilayered structures on the basis of bandwidth, absorptivity, thickness, and other important characteristics. The MM-based survey presented in this paper could be productive for the scientific community, who are having an interest in this domain. [ABSTRACT FROM AUTHOR]

Although consensus about the mechanism responsible for the recently discovered superconductivity in H2S characterized by Tc ≈ 200 K at a pressure of ≈ 150 GPa is yet to emerge, the flurry of activity it triggered has already resulted in a variety of insights and results. Taken up in this paper in the light of the insights provided by Gordon et al. (Angew. Chem. Int. Ed. 55, 3682 (2016)) and by Gor'kov and Kresin (Rev. Mod. Phys. 90, 011001 (2018)) is a detailed study of the role that the chemical potential and the effective mass of the charge carriers play in the results reported by Talantsev and co-authors (Annalen der Physics 529, 1600390 and 1700197 (2017)) for the critical current density of compressed H2S. Our framework comprises the pairing equation for moving Cooper pairs derived via the Bethe–Salpeter equation generalized to include chemical potential, temperature and an applied magnetic field, and the number equation generalized to include temperature and the applied magnetic field. We are thus led to make contact with Marel's (Physica C 165, 35 (1990)) work of about 30 years ago that was concerned with the duality in the behavior of the chemical potential in high-Tc superconductors as a function of temperature. [ABSTRACT FROM AUTHOR]

High-flux ferronickel powder cores are widely used in high-frequency transformers and other fields due to their high saturation flux density and low core loss. In this paper, FeNi@Al2O3 composites with varying Al2O3 contents (0.0–5.0 wt.%) were prepared. Their microstructure, magnetic properties, and power losses were investigated in detail. SEM morphology indicates that Fe50Ni50 magnetic powders are well coated with Al2O3. The loss analysis results show that with the increase of Al2O3 concentration, the core loss Pcv first decreased and then increased, and the coating of Al2O3 significantly reduced the eddy current loss of FeNi@Al2O3 composites. When the content of Al2O3 (1 MHz and 50 mT) is 4 wt.%, the core loss is reduced by about 75%. [ABSTRACT FROM AUTHOR]

The Conductor on Round Core (CORC®) cable is a type of high-temperature superconducting cable that is suitable for power transmission with high current density, accelerator magnets, and high field magnet devices. The CORC cable wound with RE-Ba2Cu3O7−δ (REBCO) tapes around a central metallic core can offer isotropic flexibility and good stability. In this paper, two kinds of tapes from different manufactures were selected to study the effect of the winding parameters (winding angle, former diameter, thickness of the superconducting tape, and width of the superconducting tape) on the critical performance of a single-layer CORC high-temperature superconducting cable. Based on the experimental results, a fitting equation was proposed to evaluate the critical current of the cable with different winding parameters. In addition, optimal winding parameters, which provide valuable guidance for designing a high-performance single-layer CORC cable, were proposed. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to study the influences of wire length and alternating current (AC) amplitude on the tension-stress-impedance effect of FeCoNiBSiMo microwires. In this paper, the resistance, inductance, and impedance of FeCoNiBSiMo microwires under different conditions were measured; the resistance ratio, the inductance ratio, and the impedance ratio were calculated, then the resistance ratio, inductance ratio, and impedance ratio were linearly fitted to the wire length and the alternating current amplitude, respectively. The results showed that the tension-stress-impedance effect in soft magnetic microwires was enhanced with the decrease in the wire length. The impedance ratio reached a maximum of 11%, when an alternating current of 26 MHz was applied to the soft magnetic microwire with a wire length of 1.5 cm. The tension-stress-impedance effect in the same soft magnetic microwires was enhanced with the increase of the amplitude of the applied alternating current. The impedance ratio reached a maximum of 9%, when an alternating current with an amplitude of 25 mA and a frequency of 20 MHz was applied. Both linear fitting results showed high linearity, and the highest coefficient of determination was 0.9937. [ABSTRACT FROM AUTHOR]

Superconducting power transmission is a new type of power transmission technology developed based on the characteristics of superconductors such as zero resistance and high current density. The triaxial structure is more compact and has great advantages in densely populated areas with limited transmission corridors. However, since its three-phase conductors are wound on the same former, their dimensions cannot be the same, resulting in three-phase unbalance. Three-phase unbalance causes differences in current distribution, resulting in a larger voltage difference between phases, which may reduce the current-carrying capacity of the cable. Therefore, the impedance balance design and optimization research of triaxial high-temperature superconducting (HTS) cable have important guiding significance for the development of large-capacity and long-distance superconducting cables. In this paper, the energized conductor is designed for the triaxial HTS cable, and the improved particle swarm algorithm is used for optimization research, and the optimization schemes of the three-phase single-layer and three-phase double-layer structures are compared. The reverse scheme of the single-layer structure can reduce the impedance unbalance to 1%, and the commutation scheme of the two-layer structure can reduce the impedance unbalance to 2% to achieve a three-phase impedance balance. [ABSTRACT FROM AUTHOR]

While Ted has made seminal contributions to various areas, including semiconductors and magnetism, most of his monumental opus has been devoted to superconductivity, the field in which he has played the lead role for seven decades. Ted got his B.Sc. in Chemistry in 1941 at the University of California at Berkeley, under the supervision by William Giauque. Ted stayed at Berkeley as a postdoc for few more years and published his first research papers, including four with Giauque. [Extracted from the article]

High-temperature superconducting (HTS) tape stacks have broad applications in magnetic levitation because of the uniform induced current distribution, good heat dissipation, and preferable mechanical properties. Configuration of the stack is one of the primary factors on the uniformity and strength of the trapped magnetic field. In this paper, the levitation characteristics, which are levitation force, stiffness, and rotational friction of four different YBCO tape stack configurations, were compared. It is observed from the experiments that there is an obvious influence of stack configurations on the levitation characteristics. The levitation forces gradually improve with the increase of tape pieces. While the module No.2 is an inclined stack, the levitation force is related to the inclination angle. Most of the tape stack modules can give low loss rotation in levitation, and the magnitude of the friction coefficient is close to 10− 6. By the investigation of levitation characteristics, the tape stack has great potential for the bearing application. [ABSTRACT FROM AUTHOR]

The width of REBCO (REBa2Cu3O7-x, RE: rare earths)-coated conductor is an important factor associated with AC (alternating current) loss of the tape. In the same electromagnetic environment, coils winding with narrow REBCO tapes generate less AC loss than the wide one. For a single coil, the critical current density of outer turns is higher than that of inner turns, due to the inhomogeneous distribution of magnetic field. This paper presents a multi-width technique which is applicable for single REBCO coil by partly slitting single tape in place, which can effectively reduce AC loss, while maintaining current-carrying capacity in high field. The AC loss of coils with slitting in different turns is calculated by the software of finite element modeling (FEM). The results indicate that the appropriate slitting in radially outer turns of coil appears effective to reduce AC loss, especially in the case of the coils running with high current. [ABSTRACT FROM AUTHOR]

Utilization of superconducting equipment increases every day due to availability of the HTS tapes with reasonable prices, commercially. Since 1997, many high-temperature superconducting (HTS) transformers have been designed and fabricated. In this paper, all the different developments of HTS transformer windings since 1997 will be reviewed. Additionally, the advantages and disadvantages of the application of the two main winding types (the pancake and the layer) in the HTS transformer will be studied. [ABSTRACT FROM AUTHOR]

In this paper, we report a systematic study on effect of film thickness and substrate temperature on structural and magnetic behaviour of Fe-Ga films with Cu buffer layer, deposited on Si and Si/SiO2 substrates at room and high substrate temperatures. Grazing incidence X-ray diffraction studies reveal that all the films are crystalline with disordered alpha-Fe phase, which is BCC A2 phase. At 300 °C of substrate temperature, films deposited on Si/SiO2 substrate found to nucleate L12 phase from matrix of A2 phase, which is not seen in Si based films. Irrespective of substrate material, Fe-Ga films found to exist in dual phases at 500 °C substrate temperature. Lattice strains of the films were calculated from X-ray diffraction patterns, using Williamson-Hall method. From X- ray reflectivity analysis of all the films, film density, thickness and roughness of Fe-Ga layer and buffer layer were obtained after fitting the reflectivity data. Presence of an oxide layer is also evident from reflectivity fitting analysis. From magnetization studies it is clear that, all the films exhibited strong in-plane anisotropy. Saturation magnetization of films was found to vary with change in film density and oxide layer thickness of films. Saturation magnetization of films deposited on Si substrates found to decrease with decrease in film density. Coercivity of films found to vary with change in crystallite size, interface roughness and lattice strain of films. Films deposited on Si substrates are sensitive to strain with change in film thickness and films deposited on Si/SiO2 substrates are sensitive to strain with change in deposition temperature. Coercivity in films found to decrease with decrease in film roughness, increase in crystallite size and lowering the tensile lattice strain. [ABSTRACT FROM AUTHOR]

High-temperature superconducting (HTS) cable, with massive current carrying capability and low electric power loss, is always at the cutting edge of the strong electric fields. The concentric three-phase HTS cable usually subjects to the impact of electromagnetic and mechanical forces. The forces will lead to the shape change of the cable, which may damage the cable and cause the degeneration of the critical current (Ic). In this paper, an analysis model of stress-strain and bending properties of the 10 kV/1 KA cable based on laminated theory is built. Laminated beam theory can simplify REBCO superconducting tape and concentric three-phase HTS cable to analyze stress-strain distribution. A finite element method (FEM) simulation model is established to analyze the critical bending radius of the HTS cable. Meanwhile, the normalized of the critical current of the cable is obtained at different bending radii. The analysis results will provide the theoretical basis for cable pipelaying and line relay protection in grid. [ABSTRACT FROM AUTHOR]

In this work, the effect of intrinsic doping of YGBCO target density on superconducting thin films is systematically discussed. YGBCO superconducting films generated with varying densities of YGBCO targets are all pure C-axis orientated after process optimization, but the crystallinity of the films varies, and the crystalline property of the superconducting films developed from the target with the lowest density is the best. YGBCO films made with the best density objective had in-plane and out-of-plane textures of 3.5° and 1.4°, respectively. Thin film surface morphology is affected by the density of the target material; the minimal surface roughness can be as low as 5.5 nm, The critical current of YGBCO film prepared by target with the minimum density is 135 A, and the greatest current density is 5.4× 10 6 A / cm 2 . At 4.2 K and 9 T, the critical current of the thin film created with the intrinsically nailed YGBCO target can reach 338 A. This paper prepares a 530-m-long second-generation high-temperature superconducting tape with the optimized parameters. The current of the long tape is 380 A, and the current density is 4.2× 10 6 A / cm 2 . [ABSTRACT FROM AUTHOR]

This paper explores a newly created double perovskite substance named Sr2CrMnO6 (SCMO), produced using a gel combustion method. The research delves into the material's structural, optical, and magnetic characteristics. The material's purity and the development of a monoclinic structure with space group P21/n1 (#14) were verified using Rietveld refinement of the X-ray diffraction pattern. The material's band gap, determined to be 2.5 eV through UV-Vis spectroscopy and Tauc plot analysis, indicates its potential for optoelectronic applications. At room temperature, SCMO displays paramagnetic behavior and a ferromagnetic Curie temperature of approximately 250 K, suggesting its suitability for applications in low-temperature spintronics. [ABSTRACT FROM AUTHOR]

This paper portrays the effect of growth rate on the structural, magnetic, and electrical properties of sputtered Ni thin films. Seventy-five nanometer thick Ni films were grown on Si <100> substrates at room temperature by high power impulse magnetron sputtering with varying growth rates such as 0.27, 0.57, 1.01, 2.18, and 2.65 Å/s. All the films crystallized in a single FCC type structure devoid of any impurity phase. With an increase in the growth rate, the density of the Ni films was found to increase. The surface roughness and the stresses developed in Ni films were found to decrease with an increase in the growth rate. Microstructural investigations indicated an island of surface morphology for all the films. An increase in growth rate was also found to affect the magnetic properties of Ni thin films considerably. Saturation magnetization increased with an increase in growth rate both along the in-plane and out-of-direction owing to the increase in the density of the film and reduction in stresses and surface roughness. Further, the in-plane magnetization studies also showed an increase in in-plane magnetic anisotropy in Ni films with an increase in growth rate. Evidences for improvement in the in-plane magnetic anisotropy were derived from the increase in the in-plane coercivity and remanence. Temperature variation of electrical resistivity in Ni films indicated a metallic behavior. Films grown at higher growth rates exhibited high-temperature co-efficient of resistance suitable for resistance temperature detector applications. [ABSTRACT FROM AUTHOR]

The over-current performance of high-temperature superconductors (HTSs) has been well studied. However, the superconducting devices used in power grids might also suffer from exposure to lightning current. This paper will focus on the influence of the encapsulation layer of YBCO tapes on the performance degradation of the critical current after suffering lightning current. We prepared and tested six groups of samples with different YBCO tape widths, material types of the encapsulation layer, and thicknesses of the encapsulation layer. For comparison, the performance of YBCO tape without an encapsulation layer was also analyzed. The critical current and n value of each sample were measured and calculated before and after 8/20 μs lightning current tests. Moreover, two types of damage were observed, i.e., surface melt and delamination, and the reasons were described in detail. The results of this paper could provide useful data for selecting the encapsulation layer of YBCO tapes. [ABSTRACT FROM AUTHOR]

Stochastic resonance of a giant magnetostrictive film-shape memory alloy (GMF-SMA) composite cantilever plate subjected to in-plane stochastic magnetic excitation is studied in the paper. Van der Pol terms are developed to explain the hysteretic phenomena of both GMF and SMA, and the nonlinear dynamic model of GMF-SMA composite cantilever plate subjected to in-plane stochastic magnetic excitation is established. The probability density function of the system's dynamic response is obtained, and the conditions of stochastic bifurcation are analyzed. Numerical simulation and experimental results show that the stochastic noise intensity plays an important role in the system's vibration; the system's response is little when the stochastic noise intensity is weak, and then the system's response increases with the stochastic noise, and finally decreases when the stochastic noise reaches a certain value; the stochastic resonance phenomenon occurs with the stochastic noise varying. The results of this paper are helpful for the application of GMF-SMA composite cantilever plate in vibration reduction fields. [ABSTRACT FROM AUTHOR]

In this paper, we have studied and carried out a theoretical calculation using the full-potential linearized augmented plane-wave method (FP-LAPW), based on density functional theory (DFT) and implemented in the wien2k program to investigate the structural, electronic, and magnetic properties of Ba2ErReO6 material, within the generalized gradient approximation (GGA) and generalized gradient approximation with effective Hubbard U parameter (GGA + U). According to the electronic properties and according to the GGA approximation, the results show that our material Ba2ErReO6 has a metallic character with integral magnetic moment of 5.1 µB; however, through employing the GGA + U method, the material Ba2ErReO6 radically changes in nature due to the fact that it presents a half-metallic character with a direct band gap at Γ-Γ direction in spin down channel and this for values of U ≥ 2 eV; in addition, we see that the greater the Hubbard coefficient U, the greater the energy gap of the material in its semi-conducting nature (in the spin down channel) until reaching the value of 1.96 eV corresponding to a value of 8 eV for the Hubbard coefficient U. This is a predictive study of the double perovskite compound Ba2ErReO6 based on rare earths Er and therefore constitutes a serious reason for further theoretical investigations as well as adequate experiments and this for very useful and widespread applications such as spintronic, high-performance electronic devices, and optic applications. [ABSTRACT FROM AUTHOR]

The AC losses of high-temperature superconducting (HTS) coils have a large impact on the efficiency of superconducting power devices, so the research on AC losses of HTS coils has become a current hot topic. This paper mainly studied the effects of coil turns, inter-turn spacing, and coil radius of the same superconducting coil structure on its magnetization loss in the external alternating magnetic field environment. Using the finite element simulation software, the two-dimensional axisymmetric model of single-pancake coil with double-tape winding is built. Under the condition of external alternating magnetic field with the same frequency and amplitude, the three structural parameters of superconducting coil are changed, respectively, to calculate the magnetization loss under different conditions. The simulation results are also analyzed theoretically to clarify the main reasons for the change of magnetization loss of the superconducting coil caused by the three variables. The results show that the magnetization loss of the multi-turn superconducting coil is mainly focused on the hysteresis loss. Within a certain range, the more turns of superconducting coil, the smaller the magnetization loss, while the size of inter-turn spacing, and coil radius are positively correlated with the magnetization loss of HTS coils. The simulation results are consistent with the theoretical analysis, which provides ideas and references for the subsequent study of the magnetization loss of HTS coils. [ABSTRACT FROM AUTHOR]

The alternating current (AC) loss is a key consideration of the operation economy and stability of the high temperature superconducting (HTS) cables. In this paper, the sources of the AC loss in the HTS cable are analyzed firstly. The three-phase HTS cable, adopted in the 35 kV km-level HTS cable demonstrating project in Shanghai, China, is modeled by the finite element method (FEM) to calculate the AC loss by the COMSOL Multiphysics. The AC loss of the designed 35 kV HTS cable is 1.31 W/m. The theoretical calculation method is also implemented to verify the modeling results. Furthermore, considering the on-site conditions of the demonstrating project in Shanghai, China, the calorimetric method is conducted by measuring the temperature difference between the inlet and outlet of liquid nitrogen. The obtained results provide useful indications for the future design and research of HTS AC systems. [ABSTRACT FROM AUTHOR]

The TlSr2CaCu2O7 ceramic is not easily prepared in the superconducting form but superconducts at higher temperatures than TlBa2CaCu2O7 with proper elemental substitutions. The combination of Ba and Sr in Tl(Ba,Sr)CaCu2O7 with a suitable elemental substitution is an interesting topic to study. In this paper, the effects of Ge on the superconductivity of Tl1-xGexBaSrCaCu2O7 for x = 0 to 0.6 are reported. The samples were prepared via the conventional solid-state reaction method. Powder X-ray diffraction patterns revealed a single Tl-1212 phase for the x = 0–0.2 samples. The electrical resistance versus temperature curves showed metallic normal state behavior for all samples with onset transition temperature Tc-onset between 90 and 100 K and zero transition temperature Tc-zero between 67 and 81 K. Ge-doping suppressed Tc-onset and the AC susceptibility transition temperature, Tcχ' but enhanced Tc-zero and narrowed the transition width ΔTc. The x = 0.3 sample showed the highest Tp indicating the improvement of the intergrain coupling. Tp is the peak temperature of the imaginary part, χ" of the complex susceptibility. The intergrain critical current density, Jc at the peak temperature Tp for all samples was between 15 and 18 A cm−2. Lower doping of Ge increased the homogeneities of the individual superconducting grains and enhanced intergrain coupling. The role of ionic radius and GeO2/CuO2 layers on the superconductivity of Tl(Ba,Sr)CaCu2O7 are discussed. [ABSTRACT FROM AUTHOR]

In this paper, we have studied the critical behavior at the paramagnetic ferromagnetic (PM-FM) phase transition (PT) in GdTbHoErLa (GTHEL) alloy. Near the PM-FM PT, the usefulness of the Landau theory leads to generate isothermal magnetizations M (H , T) . Through an iterative program based on the Kouvel–Fisher method, the critical exponents have been optimized. They were found to be γ = 1.04 and β = 0.82 . Thus, the exponent at the Curie temperature δ was estimated to be 2.27 . Moreover, the critical parameters are unambiguous and reasonable, but they are not matching with the conventional universality classes. [ABSTRACT FROM AUTHOR]

In a recent paper, Zhang et al. [1] studied the effect of a Pb content on the superconducting properties of Bi-2223. Some earlier, Ramírez et al. [2] explored the effect of compaction pressure on the Bi-2212. In both studies, the critical current densities were estimated and compared for a series of polycrystalline superconducting samples. The synthesis conditions for the highest critical current density were claimed in both works. This comment explains that the average granule size should be used instead of the sample size in the Bean formula for the polycrystalline superconductors synthesized by solid-state, sol–gel, electrospinning, and solution blow spinning methods. The corrected estimations for the commented articles conclude that the synthesis conditions affect both the granule size and the intragranular critical current density. The synthesis parameters for the highest critical current density conditions are clarified. [ABSTRACT FROM AUTHOR]

In this paper, a levitation pendulum composed of high temperature superconducting (HTS) bulk and rotating permanent magnet guideway (PMG) is constructed to simulate some running states of HTS maglev train when it is running relative to the magnetic track. The dynamic characteristics of the pendulum under different levitation height, running speed and magnetic flux relaxation are studied. The pendulum is found in a quasi-periodic vibration state as it runs at a low speed but gradually evolves from quasi-periodic state to chaotic state through period-doubling bifurcation with increasing the speed. In addition to the running speed, the levitation height also has a significant impact on the dynamic characteristics of the pendulum: the larger the levitation height, the lower the running speed required for the pendulum to enter the chaotic state. What is particularly striking is that according to the spectrum analysis, the factors that cause the magnetic levitation pendulum to enter the chaotic state, besides the external field drive, the magnetic flux movement inside the superconductor is another important factor, and there is no correlation between the chaotic spectrum caused by the magnetic flux movement and the external field drive frequency. [ABSTRACT FROM AUTHOR]

Fe-Co–Ni magnetic nanowire arrays (MNWs) with three-dimensional periodic structures were successfully prepared by direct current (DC) Electrodeposition. XRD results show that Fe-Co–Ni MNWs have a strong preferred orientation in the direction of the body-centered cubic structure (bcc) FeCo (110). The VSM results demonstrate that the coercivity of Fe-Co–Ni MNWs is relatively low, indicating the soft magnetic properties of Fe-Co–Ni MNWs. Further investigation of its magnetization reversal mechanism reveals the combination of curling rotation and coherent rotation. The Fe-Co–Ni MNWs with three-dimensional periodic structures prepared in this paper have potential applications in sensing and spintronic fields. [ABSTRACT FROM AUTHOR]

In this paper, magnetic and structural properties' and graphene nanoparticles' influence on photocatalytic activity of BiFeO3 ceramics are reported. BiFeO3 ceramics were prepared by the sol–gel process and sintering at different temperatures from 400 to 700 °C to get phase pure BiFeO3 ceramics. X-ray diffraction patterns indicated pure phase with sharp peaks for sample sintered at 600 °C. Rietveld analysis showed the presence of pure phase samples of rhombohedral perovskite structure with R3c symmetry expect sample sintered at 700 °C. Bond valance sum analysis showed that Fe cations are inadequately bonded, while the Bi cations are excessively bonded in BiFeO3 structure. First-order Raman modes along with few second-order modes belonging to rhombedral crystal were observed in Raman spectra. X-ray photoelectron spectroscopy showed the presence of mixed oxidation states (Fe2+/Fe3+) with Fe3+ dominance. Vibrating sample magnetometer analysis indicated weak ferromagnetism along with strong dependence of magnetic characteristics on sintering temperatures. The ferromagnetic saturation magnetization ( M FM S) and remnant magnetization decreased from 0.057 to 0.0049 emu/g and 0.0150 to 0.0009 emu/g, respectively, with increasing sintering temperature. The photocatalytic activity of pure BiFeO3 and graphene nanoparticle-modified BiFeO3 samples was recorded. It was observed that BiFeO3 with graphene nanoparticles exhibited good degradation toward methylene blue dye when exposed to visible light irradiation. [ABSTRACT FROM AUTHOR]

In order to research the effect of applied magnetic field direction on magnetic properties during oblique sputtering, in this paper, a magnetic field is applied along (or perpendicular to) in-plane projection of the incident direction of the sputtering atomic beam. VSM and magnetic spectrum results show that the applied magnetic field direction greatly affects the uniaxial anisotropy, thereby affecting the ferromagnetic resonance frequency. It was found by AFM and cross-sectional SEM that the morphology of the film and the angle of the inclined columnar crystal were completely different when the magnetic field was applied in different directions. When a magnetic field is applied along the in-plane projection of the incident direction of the sputtering atomic beam, the angle between the columnar crystal and the normal direction of the substrate is about 30°. When the magnetic field is applied to the in-plane projection perpendicular to the incident direction of the sputtering atomic beam, the columnar crystal can be seen vaguely, and there is basically no inclination angle. In addition, when the tilt angle is constant, the uniaxial anisotropy increases with the increase of target-substrate distance, which is caused by the increase of the electron beam inflow angle. [ABSTRACT FROM AUTHOR]

Fe4N/Fe3N soft magnetic composites (SMCs) prepared by gas nitriding were studied. In this paper, Fe4N was obtained by nitriding pure iron in NH3/H2, then nitrided by pure ammonia gas to obtain Fe4N/Fe3N SMCs. The morphology, structure, and magnetic properties were studied by SEM, VSM, B-H Tester, and Impedance Analyzer. With the increase of nitridation time, Fe3N content gradually increased and reached saturation after nitriding for 5 h, saturation magnetization MS decreased, and Ms was equal to 178.4 emu/g when nitriding time reached 8 h. With the increase in frequency, the effective permeability of Fe4N/Fe3N SMCs decreases, and the core loss increases. The synthesis of Fe3N generally reduced the effective permeability and loss of Fe3N/Fe4N SMCs, except for the 8 h nitrided sample. With the increase in frequency, complex permeability also decreased and tended to be stable. 8 h nitrided SMC has the largest Q and μ′. [ABSTRACT FROM AUTHOR]

In this paper, Alex and Burkard measured the dielectric constant of STO down to very low temperatures to find the polar instability of STO that was expected from its soft transverse optic mode behavior. Remembering K. Alex Müller K. Alex Müller, IBM Fellow, Professor of Physics at the University of Zurich, Nobel prize winner of physics 1987, born on April 20, 1927, in Basel, Switzerland, passed away peacefully on January 9, 2023, at the age of 95 in Zollikerberg, Switzerland. [Extracted from the article]

Design and test of superconducting magnet (SM) for a superconducting synchronous generator (SSG) are studied in this paper. First, a suitable superconducting material is selected to make SM by analyzing the characteristics and application background of the five practical superconducting materials, and the applicability and feasibility of the selected superconducting materials are demonstrated. Second, the initial structural parameters of the SM are obtained by finite element method (FEM). In addition, the influence of structural parameters of SM on the performance of SSG is analyzed by simulation. Then, an optimal algorithm combining response surface methodology (RSM) and particle swarm optimization (PSO) is proposed to optimize the structure of SM in order to give full play to the advantages of SM. The simulated results verify that the proposed optimal algorithm is feasible and effective. Finally, the prototype of SM is made by the optimized size, and the SM is tested at a low temperature to obtain the critical temperature and critical current of the SM; the experimental results verify that the designed SM can meet the requirements of SSG. [ABSTRACT FROM AUTHOR]

In this paper, first-principle calculation methods based on density functional theory are used to study the electronic structure of arsenic nitride nanoribbons (AsNNR), arsenic nitride nanoribbons passivated by hydrogen at the edges (HAsNNR), and arsenic nitride nanoribbons oxidized at the edges (OAsNNR). The results show that the spin-polarized nanoribbons are energy favorable than the non-spin-polarized nanoribbons. The zigzag type OAsNNR exhibits ferromagnetic (FM) half-metallic state. The non-equilibrium Green's function is used to study spin-polarized current of OAsNNR, and the full spin-polarized current is obtained by calculation. [ABSTRACT FROM AUTHOR]

Since the initial identification of the iron-based superconductors (IBS) in 2008, numerous studies had focused on how to improve critical current density. However, the research of quench behaviors for iron-based multi-filamentary tapes was rarely reported. It is important to understand quench behaviors, and two main parameters should be examined carefully, i.e., normal zone propagation velocity (NZPV) and minimum quench energy (MQE). In this paper, a two-dimensional quench model integrating the stationary electrodynamics equations and heat conduction equation was proposed to study the quench propagation of iron-based Sr/Ba0.6K0.4Fe2As2 (Sr/Ba122) tape in different transport currents and temperatures. MQEs and NPZVs of IBS tape were calculated by the quench model, and the results were well complied with experimentally results which verified the correctness of the proposed quench model. In addition, since iron-based superconducting coils for high magnetic field application were operating in liquid helium mostly, an experiment was performed to study the quench behaviors of Ba122 tape in liquid helium, for the purpose of understanding the stability of the iron-based superconductor and designing quench protection systems of IBS coils reliably. [ABSTRACT FROM AUTHOR]

A 5T semi-open split superconducting magnet has been recently developed at the Advanced Energy Science and Technology Guangdong Laboratory, China, in pursuit of a versatile high magnetic field test facility for measuring the field-dependent and mechanical behaviors of superconductors. It is a better candidate to generate transverse fields in a larger working region (Ø80 mm × H800 mm) and enables non-contact deformation measurements with digital image correlation (DIC). In our previous work, the simulation of the strain and the magnetic field distribution of the coil and support structure had been reported in detail; and the strain measurements for the key points were also carried out using traditional low-temperature strain gauges. However, the distributed strain of the large-scale superconducting magnet is important for exploring the whole stability. And single-point strain gauges often have difficulty measuring global strains for these complex structures. In addition, for resistance-based strain gauges, obtaining accurate strain is even more challenging due to electromagnetic interference. Therefore, in this paper, using the semi-open magnet structure, the distributed strain measurement method based on the Optical Frequency Domain Reflectometry (OFDR) principle under cryogenic and intense field is mainly validated. The global profile of the magnet system strain was monitored throughout the entire operating process, including cool-down, excitation, and warm-up. The distributed fiber strain measurements agree well with traditional single-point resistance measurements. Interesting insights into the global strain characteristics of semi-open split superconducting structures were obtained, such as the catastrophe data and asymmetrical information. The successful application of distributed fiber strain measurements provides a critical distributed detection method in superconducting magnet technology. [ABSTRACT FROM AUTHOR]