Pinning and trapped field in MgB2- and MT-YBaCuO bulk superconductors manufactured under pressure

9th International Workshop on Processing and Applications of Superconducting (RE)BCO Large Grain Materials

物理学;材料科学

Prikhna, T.^1 ; Eisterer, M.^2 ; Chaud, X.^3 ; Weber, H.W.^2 ; Habisreuther, T.^4 ; Moshchil, V.^1 ; Kozyrev, A.^1 ; Shapovalov, A.^1 ; Gawalek, W.^5 ; Wu, M.^5 ; Litzkendorf, D.^4 ; Goldacker, W.^6 ; Sokolovsky, V.^7 ; Shaternik, V.^8 ; Rabier, J.^9 ; Joulain, A.^9 ; Grechnev, G.^10 ; Boutko, V.^11 ; Gusev, A.^11 ; Shaternik, A.^1 ; Barvitskiy, P.^1

V. Bakul Institute for Superhard Materials, National Academy of Sciences of Ukraine, Avtozavodskaya Str., 2, Kiev

07074, Ukraine^1

Atominstitut, Vienna University of Technology, Stadionallee 2, Vienna

1020, Austria^2

Laboratoire National des Champs Magnétiques Intenses (LNCMI/CNRS), 25 Avenue des Martyrs, BP 166, Grenoble Cedex 9

38042, France^3

Leibniz-Institut für Photonische Technologien, Albert-Einstein-Straße 9, Jena

07745, Germany^4

Magnetworld AG, Buchaer Straße 6, Jena

07745, Germany^5

Karlsruhe Institute of Technology (KIT), Eggenstein

76344, Germany^6

Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva

84105, Israel^7

G.V. Kurdyumov Institute for Metal Physics, National Academy of Sciences of Ukraine, Kyiv

03680, Ukraine^8

Institute p', PHYMAT, UMR 6630, CNRS Universite de Poitiers, SP2MI, BP 30179, Futuroscope

F-86 962, France

(10) B. Verkin Institute for Low Temperature Physics, National Academy of Sciences of Ukraine, Kharkov

61103, Ukraine

(11) Donetsk Institute for Physics and Engineering Named after O.O. Galkin, National Academy of Sciences of Ukraine, R. Luxemburg str.72, Donetsk

114, 83114, Ukraine^9

关键词: Abrikosov vortices;    Bulk superconductors;    High critical current densities;    Large amounts;    Magnetic field variations;    Melt-textured;    Oxygen-enriched;    Pinning center;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/695/1/012001/pdf
DOI  :  10.1088/1742-6596/695/1/012001

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

The relevant pinning centers of Abrikosov vortices in MgB2-based materials are oxygen-enriched Mg-B-O inclusions or nanolayers and inclusions of MgBx(x>4) phases. The high critical current densities, jc, of 106and 103A/cm2at 1 and 8.5 T, respectively, at 20 K can be achieved in polycrystalline materials (prepared at 2 GPa) containing a large amount of admixed oxygen. Besides, oxygen can be incorporated into the MgB2structure in small amounts (MgB1.5O0.5), which is supported by Auger studies and calculations of the DOS and the binding energy. The jcof melt textured YBa2Cu3O7-δ(or Y123)-based superconductors (MT-YBaCuO) depends not only on the perfectness of texture and the amount of oxygen in the Y123 structure, but also on the density of twins and micro-cracks formed during the oxygenation (due to shrinking of the c-lattice parameter). The density of twins and microcracks increases with the reduction of the distance between Y2BaCuO5 (Y211) inclusions in Y123. At 77 K jc=8•104A/cm2in self-field and jc=103A/cm2 at 10 T were found in materials oxygenated at 16 MPa for 3 days with a density of twins of 2235 per μm (thickness of the lamellae: 45-30 nm) and a density of micro-cracks of 200280 per mm. Pinning can occur at the points of intersection between the Y123 twin planes and the Y211 inclusions. MTYBaCuO at 77 K can trap 1.4 T (38×38×17 mm, oxygenated at 0.1 MPa for 20 days) and 0.8 T (16 mm in diameter and 10 mm thick with 0.45 mm holes oxygenated at 10 MPa for 53 h). The sensitivity of MgB2to magnetic field variations (flux jumps) complicates estimates of the trapped field. At 20 K 1.8 T was found for a block of 30 mm in diameter and a thickness of 7.5 mm and 1.5 T (if the magnetic field was increased at a rate of 0.1 T) for a ring with dimensions 24×18 mm and a thickness of 8 mm.