Modern superconductive materials for electrical machines and devices working on the principle of levitation

Abstract

The peculiarities of high-pressure synthesis of highly dense nanostructural MgB 2 -based superconductive materials, of thermobaric treatment of MT-YBCO (melt-textured YBa 2 Cu 3 O 7-dbased superconductor), high-pressure sintering of YBa 2 Cu 3 O 7-d , oxygenation of MT-YBCO under high isostatic pressure of oxygen and processes of formation of superconductive junctions between MT-YBCO blocks are considered. The attained level of superconductive and mechanical properties of such materials and junctions make them promising for application in cryogenic devices working on the principle of levitation: electricmotors, generators, pumps for liquid-gas transfer, magnetic bearings, flywheels, fault current limiters, maglev transport, etc. High-pressure synthesized MgB 2 (with Ti additions) blocks were for the first time tried in the superconductive electricmotor at 20 K and demonstrated an efficiency similar to MT-YBCO (at the same working temperature).

Self-heating of bulk high temperature superconductors of finite height subjected to a large alternating magnetic field

“…Bulk melt-processed Y-Ba-Cu-O (YBCO), high temperature superconductors (HTS) are usually fabricated in disc or cylindrical geometries for various permanent magnet-like applications [1,2], such as rotating machines [3][4][5][6] or magnetic bearings [7][8][9][10], due to their ability to trap large magnetic inductions [11][12][13][14]. In some applications, however, the bulk superconductor may experience periodic variations of the applied magnetic field that are caused, for example, by vibrations or irregular magnetization by a permanent magnet interacting with the sample [15,16].…”

Metal Organic Frameworks Assembled from Y(III), Na(I), and Chiral Flexible-Achiral Rigid Dicarboxylates

“…We have chosen terephthalic acid ( H 2 BDC ) which has been used extensively as an organic spacer, and its extended analogue biphenyl-4,4′-dicarboxylic acid ( H 2 biBDC ), because these rigid ligands (i) are able to establish a bridge between metal centers, affording frameworks with large pores, − and (ii) may enhance the fluorescence of the Ln(III) ions, via the so-called antenna effect. , The combination of this mixed-ligand system with rare-earth ions, such as the small Y(III), allows the synthesis of unusual coordination polymers with interesting properties. The yttrium coordination polymers are relatively limited compared with the f-block metal ions, although yttrium is widely used in laser crystals, − and superconductive materials. − …”