Flux‐pinning properties of nanocrystalline HfO2 added YBa2Cu3O7−δ superconductor. Issue 4 (9th December 2013)

• Record Type: Journal Article
• Authors: Rejith, Pullanhiyodan Puthiyaveedu; Vidya, Sukumariamma; Vipinlal, ; Solomon, Sam; Thomas, Jijimon Kumpukattu
• Is Part Of: Physica status solidi. Volume 251:Issue 4(2014:Apr.)
• Page Start: 809
• Page End: 814
• Publication Date: 2013-12-09
• Subjects: Solid state physics -- Periodicals; Solids -- Periodicals; Atomic structure -- Periodicals; 530.41
• DOI: 10.1002/pssb.201349019
• Languages: English
• ISSNs: 0370-1972

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="pssb201349019-sec-0001" sec-type="section"> <p>The effect of addition of different weight percentages of nanocrystalline HfO<sub>2</sub>, synthesized through a modified combustion method in bulk coarse‐grained orthorhombic YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7−<italic>δ</italic></sub> 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<sub>2</sub>HfO<sub>5.5</sub> in the superconductor without deteriorating the superconducting properties. The variation of sintering temperature, density, critical transition temperature (<italic>T</italic><sub>c</sub>), magnetic field dependence of critical current density (<italic>J</italic><sub>c</sub>), and flux‐pinning force (<italic>F</italic><sub>p</sub>) of YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7−<italic>δ</italic></sub> having different proportions of YBa<sub>2</sub>HfO<sub>5.5</sub> formed in the matrix were studied in detail. The samples showed a transition temperature (<italic>T</italic><sub>c</sub>) of ∼92 K and the self‐field critical current density (<italic>J</italic><sub>c</sub>) increases significantly up to an optimum value of 5.42 × 10<sup>4</sup> A cm<sup>−2</sup> for 2 wt% addition of nano HfO<sub>2</sub>. The enhancement of the critical current density in the YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7−<italic>δ</italic></sub>‐HfO<sub>2</sub> samples is attributed to the presence of the nonreacting YBa<sub>2</sub>HfO<sub>5.5</sub> phase, formed due to the addition of HfO<sub>2</sub> as artificial pinning center. The formation of YBa<sub>2</sub>HfO<sub>5.5</sub> in YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7−<italic>δ</italic></sub> bulk superconductor also enhances the pinning force density from 3 × 10<sup>6</sup> to 30.4 × 10<sup>6</sup> N m<sup>−3</sup> at 77 K.</p> </sec> </abstract>