Magnetic and transport measurements on melt-textured DyBCO single domains

Abstract

In this communication we report critical current measurements of melt processed DyBa 2 Cu 3 O 7-x samples determined by several measuring techniques. First the material was characterized by AC susceptibility and DC magnetization. The results are characteristic of good quality melt-processed (RE)BCO material with T c ≈ 89 K and J c (77 K, 1 T) ≈ 10 4 A/cm 2 . Next, pulsed currents were used in order to determine both I-V curves and transport critical currents. The origin of the discrepancy between transport and magnetic data has been discussed. The results point out significant local variations of the critical current density throughout the single domain.

Unexpected transport and magnetic properties in Y–Ba–Cu–O superconductors

“…It is ∼1 × 10 6 A/cm 2 at zero fields and goes down to ∼3 × 10 5 A/cm 2 at 40,000 Oe. With the increase of temperature to 77 K, the intragrain J cm decreases sharply and takes values about 20–50 times in magnitude less than that of at 10 K. For instance, the intragrain J cm was calculated as ∼4 × 10 4 A/cm 2 at zero fields and 77 K. These values are, respectively, high for a polycrystalline superconductor having similar structure and even at the level of the J c ‐values of melt‐textured High T c cuprates 33–36. Such a high temperature dependence of the intragrain J cm shows that point defects, which act as pinning center at 10 K, are intensively present in the microstructure and they become ineffective at 77 K. Furthermore, the intragrain J cm also seems to be very sensitive to the applied field at 77 K. It is ∼7000 A/cm 2 under magnetic field of 1000 Oe.…”

Transport Current Measurement of $I_{c}(T, B,\theta)$ and $n(T, B,\theta)$ for a Bulk REBCO Superconductor

“…Due to these difficulties, a comprehensive dataset of transport J c and n-values for REBCO bulks is yet to be published, with previous works being predominantly focused on the LN2 temperature, self-field case for YBCO [28]- [32]. Other bulks such as DyBCO, (NdEuGd)BCO and GdBCO-Ag have also been investigated, but to a lesser degree [14], [33], [34]. Some critical current angle-dependence has been measured, such as in [28], [29], however the I c data is mostly sparse, unpublished for n-values and over 20 years old, when bulk manufacturing technology was less refined.…”

Characterization of High-Temperature Superconductor Bulks for Electrical Machine Application

“…This means the determination of the critical current density J C . Different classical methods have been used for small samples [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. The goal of these classical methods is mainly to obtain the dependence of J C on the magnetic field B and temperature of the HTS material.…”