8 research outputs found
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Improved trapped field performance of single grain Y‐Ba‐Cu‐O bulk superconductors containing artificial holes
Abstract: The intrinsic mechanical properties of single‐grain RE‐Ba‐Cu‐O bulk high‐temperature superconductors can be improved by employing a thin‐wall geometry. This is where the samples are melt‐processed with a predefined network of artificial holes to decrease the effective wall thickness. In this study, the tensile strengths of thin‐wall YBCO disks were determined using the Brazilian test at room temperature. Compared with conventional single grain YBCO disks, the thin‐wall YBCO disks displayed an average tensile strength that is 93% higher when the holes were filled with Stycast epoxy resin. This implies a thin‐wall sample should, in theory, be able to sustain a trapped field that is 39% higher without exceeding the mechanical limit of the sample. High‐field magnetization experiments were performed by applying magnetization fields of up to 11.5 T, specifically to break the samples in order to verify the effect of increased mechanical strength (and improved cooling) on the ability of bulk (RE)BCO to trap field successfully. The standard YBCO sample failed when it was magnetized with a field of 10 T at 35 K, suffering permanent damage. As a result, the standard sample could only trap a maximum surface field of 7.6 T without failure. On the other hand, the thin‐wall YBCO sample survived all magnetization cycles, including a maximum magnetization field of 11.5 T at 35 K, demonstrating a greater intrinsic ability to withstand significantly higher electromagnetic stresses. By subsequently field‐cooling the thin‐wall sample with 11 T at 30 K, a surface field of 8.8 T was trapped successfully without requiring any external ring reinforcement
Thermodynamic Properties of Stoichiometric Non-Superconducting Phase Y2BaCuO5
Y2BaCuO5 often occurs as an accompanying phase of the well-known high-temperature superconductor YBa2Cu3O7 (also known as YBCO). Y2BaCuO5, easily identifiable due to its characteristic green coloration, is often referred to as ‘green phase’ or ‘Y-211’. In this contribution, Y2BaCuO5 phase was studied in detail with a focus on its thermal and thermodynamic properties. Energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were employed in the study of sample’s morphology and chemical composition. XRD data were further analyzed and lattice parameters refined by Rietveld analysis. Simultaneous thermal analysis was employed to study thermal stability. Particle size distribution was analyzed by laser diffraction. Finally, thermodynamic properties, namely heat capacity and relative enthalpy, were measured by drop calorimetry, differential scanning calorimetry (DSC), and physical properties measurement system (PPMS). Enthalpy of formation was assessed from ab-initio DFT calculations
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Statistical evaluation of the mechanical and flux trapping properties of standard and thin-wall EuBCO(Ag) bulk superconductors
The mechanical and flux trapping properties of 19 EuBCO(Ag) and 20 thin-wall EuBCO(Ag) bulk superconductors were investigated statistically and compared to those observed for YBCO using Brazilian testing and high field magnetization. The average trapped fields of EuBCO(Ag) and thin-wall EuBCO(Ag) bulk superconductors were significantly higher than those of YBCO bulk samples at 77 K measured under similar experimental conditions. However, due to the wide range of trapped field data for both materials, a statistical overlap was observed between the highest trapped fields observed for YBCO and the lowest values observed for EuBCO(Ag) bulk superconductors. All EuBCO(Ag) bulk materials measured in this study exhibit a superior tensile strength compared to YBCO bulk single grains. Unlike the case of YBCO, however, the introduction of artificial holes to EuBCO(Ag) bulk superconductors prior to melt processing was observed to decrease the average tensile strength of the single grain. Surprisingly, despite their superior mechanical and flux pinning properties, EuBCO(Ag) bulk superconductors do not exhibit enhanced performance when exposed to high fields at low temperatures.Engineering and Physical Sciences Research Council (Grant/Award Numbers: EP/T014679/1, EP/R513180/1), Henry Royce Institute (Grant/Award Numbers: EP/P024947/1, EP/R00661X/1
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Research Data supporting "Statistical evaluation of the mechanical and flux trapping properties of standard and thin-wall EuBCO(Ag) bulk superconductors"
This dataset contains supporting information for the journal article “Statistical evaluation of the mechanical and flux trapping properties of standard and thin-wall EuBCO(Ag) bulk superconductors”.
The file “README.txt” contains detailed information about the data measurement and evaluation.
The file “Raw_data.xlsx” contains the raw data used for the plots illustrated in figures 3,4 and 6.
The file “Determination_Weibull_modulus.xlsx” explains the calculation of the Weibull modulus for EuBCO(Ag), thin wall EuBCO(Ag) and Stycast filled thin wall EuBCO(Ag) bulk materials.Engineering and Physical Sciences Research Council (Grant/Award Numbers: EP/T014679/1, EP/R513180/1), Henry Royce Institute (Grant/Award Numbers: EP/P024947/1, EP/R00661X/1
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Statistical evaluation of the mechanical and flux trapping properties of standard and thin‐wall EuBCO(Ag) bulk superconductors
Publication status: PublishedAbstractThe mechanical and flux trapping properties of 19 EuBCO(Ag) and 20 thin‐wall EuBCO(Ag) bulk superconductors were investigated statistically and compared to those observed for YBCO using Brazilian testing and high‐field magnetization. The average trapped fields of EuBCO(Ag) and thin‐wall EuBCO(Ag) bulk superconductors were significantly higher than those of YBCO bulk samples at 77 K measured under similar experimental conditions. However, due to the wide range of trapped field data for both materials, a statistical overlap was observed between the highest trapped fields observed for YBCO and the lowest values observed for EuBCO(Ag) bulk superconductors. All EuBCO(Ag) bulk materials measured in this study exhibit a superior tensile strength compared to YBCO bulk single grains. Unlike the case of YBCO, however, the introduction of artificial holes to EuBCO(Ag) bulk superconductors prior to melt processing was observed to decrease the average tensile strength of the single grain. Surprisingly, despite their superior mechanical and flux pinning properties, EuBCO(Ag) bulk superconductors do not exhibit enhanced performance when exposed to high fields at low temperatures.</jats:p
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Research data supporting "Effect of Y-211 particle size on the growth of single grain Y–Ba–Cu–O bulk superconductors"
The files provided contain the raw 211 particle distribution data, DTA, XRD and trapped field data used to produce the figures presented in the paper. Further documentation is provided in the origin files.This work was supported by the EPSRC, Czech Ministry of Industry and Trade EP/K02910X/