An Effective Approach for the Development of Reliable YBCO Bulk Cryomagnets with High Trapped Field Performances

Abstract

Widespread use of YBa2Cu3O7‐δ (Y123) bulk superconductors as source of strong magnetic fields requires development of high‐performance materials sufficiently reliable with improved thermal transfer ability. An effective approach based primarily on the growth of bulk Y123 single domains comprising a holes‐network to diminish the oxygen diffusion paths is reported here, as well as their progressive annealing at high temperature under oxygen pressure to reduce undue stresses and processing time. Finely, it aims to stimulate the thermal exchange inside the superconductor and compensate for induced magnetic stresses during the field‐trapping process. The approach brings considerable time and energy savings, and turns out to knock down barriers having stymied hitherto the use of Y123 bulk superconductors for engineering applications. Indeed, it enables the achievement of a pore‐free and crack‐free microstructure yielding marked fracture toughness and promoting large size persistent current loops, thereby boosting the trapped field performances. The fostering of the internal thermal exchange leads the maximum trapped field Bmax to shift to higher temperatures by up to 14 K. A value Bmax of 6.34 T is attained at 17 K on ≈16 mm‐diameter reinforced pellet (disk area s = 1.99 cm2), resulting in an outstanding field density Bmax/s=3.19 Tcm−2.

Improvement of critical current density of MgB2 bulk superconductor processed by Spark Plasma Sintering

“…The measurements were made by scanning a Hall sensor 10 mm above the bulk surface. The trapped field distribution shows a single dome as in single domain YBaCuO bulks 8 . This conical distribution of the magnetic field can be associated to the homogeneous transport of the current through the grain boundaries.…”

c-Oriented YBa2Cu3O7−δ film with embedded a-oriented grains grown by liquid phase epitaxy under fine-tuning supersaturation

“…Since its discovery in 1987, the YBa 2 Cu 3 O 7À (Y123) hightemperature superconductor has demonstrated attractive superconducting properties, which are fascinating for both fundamental studies and practical applications (Norton et al, 1989;Terashima et al, 1991;Moeckly & Char, 1997;Kaestner et al, 2000;Boris et al, 2013;Kenfaui et al, 2014;Achkar et al, 2014). For decades, the control of the preferred orientations has been a crucial issue owing to the notable intrinsic anisotropy of the coherence length along the a (and/or b) axis and c axis of the Y123 film (Welp et al, 1989).…”

Effects of Gd211 Particles Characteristic in the Precursor Pellets on the Levitation Force of Single-Domain GdBCO Bulks Prepared by the Gd + 011 TSIG Method

“…ese advantages lead to many applications such as magnetic bearing, flywheel, high-field permanent magnets, and levitated transportation systems [1][2][3][4][5][6]. In order to obtain large single-grain REBCO bulks without weak links, the top seeding technique is employed to avoid the heterogeneous nucleation and promote the growth of the REBa 2 Cu 3 O 7-y grain epitaxial grown from the seed to a large scale [7][8][9][10]. Top-seeded infiltration growth (TSIG) technique is one of the most popular methods for fabrication of single-grain REBCO bulk superconductors.…”