Fabrication and properties of (Hg_0.8Re_0.2)Ba₂Ca₂Cu₃O_xsuperconducting thick films

Abstract

Approximately 50 µm thick epitaxial c-axis orientated (Hg0.8Re0.2)Ba2Ca2Cu3Ox superconducting films have been prepared on MgO(100) substrates using a spraying process and post-Hg-vapour annealing. The effects of the heating temperature–time combinations and the filling factor of Hg (ffHg) on the physical, electrical and magnetic properties of the thick films have been investigated. The interesting observation was the formation of a thick interfacial layer between the film and the substrates. This interfacial layer was found to be protective against excessive diffusion and dissolution of the Mg2+ ions from the substrate or counter-diffusion of Ba, Ca and Cu ions from the films. The XRD investigations showed that the a–b plane of the HgRe-1223 phase aligns parallel to the substrate surface. The best Tc and Tzero were found to be 131.9 and 129.3 K, respectively. Magnetic properties up to 5 T have been investigated. The calculated value of critical current density, Jc, was found to be 4.82 × 105 A cm−2 at 4.5 K. The results obtained suggested that fabrication of HgRe-1223 thick film superconductors using a spraying process with 130 K transition is possible and they are very promising particularly for electronic applications.

Effects of thickness on the grain alignment and Jc properties of (Hg0.8Re0.2)Ba2Ca2Cu3Ox superconductor thick films

“…The solution was then sprayed onto the single crystal MgO(1 0 0) substrates and heated as explained in Ref. [2].…”

“…Several groups have recently reported the growth of Hgbased films with thicknesses between 1 and 80 lm [1][2][3]. Most of these films have showed single phase transition above 120 K with significantly high J c values.…”

Synthesis and Structural Characterization of Hg(Re)-Pb-Ca-Ba-Cu-O Superconducting Thin Films Grown by Spray Pyrolysis

“…The n = 3 compound of this series has the T c record of 135 K at atmospheric pressure [2]. On account of the difficulty for obtaining high-quality samples in this system and the complex reaction in the preparation, it is important for both fundamental and application fields to study and to understand the dynamics in the preparation of precursor phases applied in the growing of thin films [3,4]. In order to determine optimal methods of preparation by controlling the deposition and annealing parameters we have done a systematic study in precursor films for the preparation of Hg-based thin films.…”