Impact of Boron Nitride Additive on the Phase Formation and Transport Properties of Bi(Pb)-2223 Superconductor
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ct of Boron Nitride Additive on the Phase Formation and Transport Properties of Bi(Pb)-2223 Superconductor A. S. Kuzanyana, *, N. G. Margianib, G. A. Mumladzeb, I. G. Kvartskhavab, G. R. Badalyana, and V. V. Zhghamadzeb aInstitute
for Physical Research, NAS of Armenia, Ashtarak, Armenia Institute of Cybernetics. Vladimir Chavchanidze Georgian Technical University, Tbilisi, Georgia *e-mail: [email protected]
b
Received January 29, 2020; revised February 25, 2020; accepted March 5, 2020
Abstract—Doping of a high-temperature Bi(Pb)-2223 superconductor with various additives, which can act as pinning centers and / or accelerate the formation of a superconducting phase, is an effective tool for obtaining Bi(Pb)-2223 samples with improved characteristics. In this paper, we studied the effect of the addition of hexagonal boron nitride (h-BN) on the phase formation and critical transport current density of ceramic samples Bi(Pb)-2223. Samples with a nominal composition of Bi1.7Pb0.3Sr2Ca2Cu3Oy [BN]x, x = 0–0.25 were prepared by the solid-phase reaction method. Two different doping methods were used: the introduction of hand-ground BN powder at the initial stage of synthesis and the addition of BN powder subjected to high-energy grinding in a ball mill before pelletizing. The phase composition of the obtained samples was studied by X-ray diffraction. The microstructure and elemental composition of the samples were studied using a scanning electron microscope with an X-ray microanalyzer. The resistivity and critical current density were measured using the standard four-probe method. The results show that boron nitride is a suitable additive to increase the rate of formation and critical transport current density Bi(Pb)-2223. Keywords: Bi(Pb)-2223 phase, doping, high energy ball milling, phase formation, critical current density DOI: 10.3103/S1068337220030081
1. INTRODUCTION Undoubtedly, the discovery of high-temperature superconductivity (HTSC) at Tc = 38 K in LSCO cuprates was one of the most significant achievements of 20th-century science [1]. Thanks to efforts of different research groups, the critical temperature of a new class of superconductors increased rapidly. Superconductivity was found in YBCO (Tc = 93 K) [2], Tl-2201 (Tc = 95 K) and Tl-2223 (Тс = 125 K) [3, 4], Bi-2212 (Тс = 95 K) and Bi-2223 (Тс = 110 K) [5, 6]. Among the first researchers in this new direction were also representatives of the Institute for Physical Research of the NAS of Armenia and the Institute of Cybernetics of Technical University of Georgia. In particular, the effect of more than fifteen impurities on the superconducting properties of the Bi-2223 phase and the formation of unstable magnetic anomalies in Bi-containing cuprates were studied in detail [7–16]. Among the high-temperature superconducting materials, the compound Bi(Pb)-2223 is one of the most promising for applications in science and technology. The synthesis of single-phase Bi-2223 is a difficult problem since the kinetics of phase formation is very slow. To obtain a mater
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