Neutron-radiation-induced flux pinning in Gd-doped YBa sub 2 Cu sub 3 O sub 7 minus x and GdBa sub 2 Cu sub 3 O sub 7 minus x

• Published in: Physical review. B, Condensed matter Condensed matter, 1992-11, Vol.46:18
• Main Authors: Sickafus, K.E., Willis, J.O., Kung, P.J., Wilson, W.B., Parkin, D.M., Maley, M.P., Clinard, F.W. Jr, Salgado, C.J., Dye, R.P., Hubbard, K.M.
• Format: Article
• Language: English
• Subjects: 400600 > Radiation Chemistry; 665300 > Interactions Between Beams & Condensed Matter-- (1992-); ABSORPTION; ALKALINE EARTH METAL COMPOUNDS; ALLOYS; BARIUM COMPOUNDS; BARIUM OXIDES; BARYONS; CHALCOGENIDES; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COPPER COMPOUNDS; COPPER OXIDES; CRITICAL CURRENT; CRYSTAL DEFECTS; CRYSTAL STRUCTURE; CURRENTS; DEFECTS; ELECTRIC CONDUCTIVITY; ELECTRIC CURRENTS; ELECTRICAL PROPERTIES; ELEMENTARY PARTICLES; FAST NEUTRONS; FERMIONS; FRENKEL DEFECTS; GADOLINIUM ADDITIONS; GADOLINIUM ALLOYS; GADOLINIUM COMPOUNDS; GADOLINIUM OXIDES; HADRONS; HIGH-TC SUPERCONDUCTORS; IRRADIATION PROCEDURES; MAGNETIC FLUX; MATERIALS SCIENCE; MINERALS; NEUTRONS; NUCLEONS; OXIDE MINERALS; OXIDES; OXYGEN COMPOUNDS; PEROVSKITE; PEROVSKITES; PHYSICAL PROPERTIES; POINT DEFECTS; RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; RARE EARTH ADDITIONS; RARE EARTH ALLOYS; RARE EARTH COMPOUNDS; SORPTION; SUPERCONDUCTIVITY; SUPERCONDUCTORS; THERMAL NEUTRONS; THERMODYNAMIC PROPERTIES; TRANSITION ELEMENT COMPOUNDS; TRANSITION TEMPERATURE; VACANCIES; YTTRIUM COMPOUNDS 360207 > Ceramics, Cermets, & Refractories-- Superconducting Properties-- (1992-); YTTRIUM OXIDES
• ISSN: 0163-1829; 1095-3795
• DOI: 10.1103/PhysRevB.46.11862

The critical current density {ital J}{sub {ital c}} in Y{sub 0.9}Gd{sub 0.1}Ba{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} was found to increase relative to the unirradiated value following neutron irradiations in a mixed-spectrum reactor (total neutron fluences ranged between 1{times}10{sup 17} and 2{times}10{sup 18} {ital n}/cm{sup 2}). Additional neutron irradiations of structurally similar GdBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} were carried out in either a highly thermalized or a pure fast-neutron environment (in the same reactor). This was done to determine whether enhancements in {ital J}{sub {ital c}} are to be attributed to defects arising from interactions with thermal neutrons ({ital E}{sub {ital n}}{similar to}0.025 eV) or with fast neutrons ({ital E}{sub {ital n}}{gt}0.1 MeV). Magnetic-hysteresis measurements on these samples indicate that flux pinning (and thereby {ital J}{sub {ital c}}) is enhanced by fast-neutron irradition, but not by thermal-neutron irradiation. On the other hand, the critical temperature {ital T}{sub {ital c}} is significantly altered by exposure both to thermal and fast neutrons. It is proposed that thermal neutrons induce the formation of Frenkel pair defects on the rare-earth sublattice, but that these point defects do not serve as effective flux-pinning centers.