Premium
Flux‐pinning properties of nanocrystalline Hf O 2 added YB a 2 C u 3 O 7− δ superconductor
Author(s) -
Rejith Pullanhiyodan Puthiyaveedu,
Vidya Sukumariamma,
Solomon Sam,
Thomas Jijimon Kumpukattu
Publication year - 2014
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201349019
Subject(s) - flux pinning , materials science , superconductivity , nanocrystalline material , microstructure , condensed matter physics , orthorhombic crystal system , sintering , phase (matter) , transition temperature , pinning force , analytical chemistry (journal) , high temperature superconductivity , crystallography , nanotechnology , critical current , composite material , chemistry , crystal structure , physics , organic chemistry , chromatography
The effect of addition of different weight percentages of nanocrystalline HfO 2 , synthesized through a modified combustion method in bulk coarse‐grained orthorhombic YBa 2 Cu 3 O 7− δ powder was studied. The structure and microstructure of the samples examined by X‐ray diffraction (XRD) and scanning electron microscopy (SEM) showed the formation of a secondary phase YBa 2 HfO 5.5 in the superconductor without deteriorating the superconducting properties. The variation of sintering temperature, density, critical transition temperature ( T c ), magnetic field dependence of critical current density ( J c ), and flux‐pinning force ( F p ) of YBa 2 Cu 3 O 7− δ having different proportions of YBa 2 HfO 5.5 formed in the matrix were studied in detail. The samples showed a transition temperature ( T c ) of ∼92 K and the self‐field critical current density ( J c ) increases significantly up to an optimum value of 5.42 × 10 4 A cm −2 for 2 wt% addition of nano HfO 2 . The enhancement of the critical current density in the YBa 2 Cu 3 O 7− δ ‐HfO 2 samples is attributed to the presence of the nonreacting YBa 2 HfO 5.5 phase, formed due to the addition of HfO 2 as artificial pinning center. The formation of YBa 2 HfO 5.5 in YBa 2 Cu 3 O 7− δ bulk superconductor also enhances the pinning force density from 3 × 10 6 to 30.4 × 10 6 N m −3 at 77 K.