Influence of Ba²⁺ consumption and intermediate dwelling during processing of YBa₂Cu₃O₇ nanocomposite films

Abstract

Achieving high-critical current densities (J c ) with small artificial pinning centers is a crucial challenge for YBa 2 Cu 3 O 7−δ (YBCO) nanocomposite thin films fabricated using chemical solution deposition methods. In this work, the YBCO texture, structure purity, and its J c properties were improved by understanding the influence of preformed ZrO 2 nanocrystals (Ba 2+ consumption) during the nucleation and growth mechanism. This comprehensive study leads to an additional intermediate dwelling step during thermal process to increase the YBCO nuclei density before the YBCO growth, resulting to a self-field J c of 5-6 MA/cm 2 at 77 K for undoped and ZrO 2 -doped YBCO films. Counter-intuitively, the space and size distribution of the ZrO 2 nanocrystals in the YBCO matrix are independent of this intermediate dwelling step. K E Y W O R D S chemical solution deposition, low-fluorine YBCO, nanocomposite, nanoparticles, vortex pinning

Superconducting HfO2-YBa2Cu3O7−δ Nanocomposite Films Deposited Using Ink-Jet Printing of Colloidal Solutions

“…This means that HfO 2 nanocrystals reacted with the Ba 2+ ions, leading to the formation of BaHfO 3 particles in the YBCO matrix. Nevertheless, our previous work [39] demonstrated that the reactivity of preformed ZrO 2 nanocrystals results in a delay rather than in a degradation of the YBCO nucleation and growth. This growth delay can be circumvented via the introduction of an intermediate dwelling step, yielding an increase of J c [39].…”

“…Nevertheless, our previous work [39] demonstrated that the reactivity of preformed ZrO 2 nanocrystals results in a delay rather than in a degradation of the YBCO nucleation and growth. This growth delay can be circumvented via the introduction of an intermediate dwelling step, yielding an increase of J c [39]. However, Pop et al [34] has recently printed a low-fluorine-based YBCO precursor solution with additives on a LaAlO 3 substrate with a final thickness of 0.6-1.2 µm via a single deposition, yielding a fairly good J c value of 2.0-2.7 MA•cm −2 and an I c value of 240 A at 77 K ( Table 2).…”

“…The single-or multi-printed layers were dried at 85 • C on a hotplate in ambient atmosphere for 5 min and subsequently pyrolyzed by heating to 400 • C with a heating rate of 3-5 • C•min −1 in a humidified O 2 atmosphere. To obtain the desired superconducting film, the pyrolyzed YBCO films were subsequently exposed to a two-step, high-temperature thermal treatment at 640 • C for 60 min (nucleation) and at 800 • C for 70 min (growth) in a humid 100 ppm O 2 in N 2 atmosphere, which was switched to dry O 2 at 450 • C for 2 h during the annealing step [39].…”

“…, starting from preformed ZrO 2 nanocrystals deposited via the trifluoroacetic route (6.0 GN•m −3 )[23] and the propionate route (7.3 GN•m −3 )[39]. However, these F p,max values were still lower than for self-assembled BaZrO 3 particles via the trifluoroacetic route (21 GN•m −3 )[26].…”

CSD-Grown Y1−xGdxBa2Cu3O7−δ-BaHfO3 Nanocomposite Films on Ni5W and IBAD Technical Substrates

“…Apart from the benefits of RE mixing, and in order to improve the pinning properties in such films further, secondary phases can be included in the matrix to produce REBCO nanocomposites. This topic has been extensively studied by many groups evidencing that the in-field transport properties of REBCO films can be extensively enlarged by using both the "in situ" and the "ex situ" approaches [29][30][31][32][33][34][35][36].…”