Structural, Electrical, and Magnetic Properties of the Co-Substituted Bi-2212 System Textured by Laser Floating Zone Technique

Abstract

In this work, Bi 2 Sr 2 CaCu 2-x Co x O y (x =0.0, 0.05, 0.10, and 0.25) textured superconductors were prepared by a LFZ melting technique. In all cases, the powder X-ray diffraction patterns of samples show that Bi-2212 phase is the major one. All samples have good oriented structure, which is a typical picture for superconductors prepared by LFZ method.Magnetization hysteresis loops, made for all samples at two different temperatures, showed that the loops become narrower with increasing temperature and doping levels. In addition, the effect of Co doping on the critical current density, J C , of Bi 2 Sr 2 CaCu 2-x Co x O y has been estimated from hysteresis loop measurement by using Bean's model. The increase of Co amount in Bi 2 Sr 2 CaCu 2-x Co x O y structure significantly decreases the critical current density, showing worse connectivity of the grains. All the results indicate that Co substitution for Cu produces the deterioration on the superconducting properties, compared with the undoped samples.

Improvement of the intergranular pinning energy in the Na-doped Bi-2212 superconductors

“…In addition, the material preparation technique plays a crucial role, as important as the substitutions, creating pinning centers in BSCCO systems. In order to easily obtain very homogeneous samples, the polymer matrix route is a very adequate solution methods, as reported in previous works [25][26][27][28][29][30]. In this method, smaller particle sizes than the produced by the classical solid state method, are is obtained leading to higher reactivity of powders and lower amount of secondary phases.…”

Improvement of superconducting properties in Na-doped BSCCO superconductor

“…Since the discovery of Bi-based high-temperature superconductors [1], which are among the most promising materials for technological and industrial applications, many experimental studies have been performed [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] in order to improve their critical temperature (Tc), critical current density (Jc), and better understand the structural properties of the system. The BSCCO families can be described by the Bi 2 Sr 2 Ca n-1 Cu n O 2n+4+y general formula, where n=1, 2 and 3.…”

Effect of Yttrium substitution on superconductivity in Bi-2212 textured rods prepared by a LFZ technique

“…The n value indicates the number of CuO 2 layers in the crystal structure, producing the Bi-2201, Bi-2212 and Bi-2223 phases with critical temperatures, Tc's, of about 20, 85, and 110 K, respectively [1,2]. Since their discovery, many experiments have been performed to better understand their structural and physical properties of the system, and to improve their critical temperature (Tc) and critical current density (Jc) [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. After these works, it is well-known that the Bi-2212 phase is the most stable and easy to prepare among the high-Tc phases.…”