Investigation of Structural and Superconducting Properties of Cr Added Bi-2212 Superconducting Ceramics

Abstract

This study reports the effect of Cr addition on the structural and superconducting properties of Bi 1.8 Sr 2.0 Crx Ca 1.1 Cu 2.1 O y superconductor with x = 0, 0.1, 0.3, 0.5 0.7, and 1 by means of X-ray analysis (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and resistivity measurements. The samples studied in this work were prepared using the standard solid-state reaction method. Zero resistivity transition temperatures (T c ) are qualitatively estimated from the dc resistivity measurements. The zero resistivity transition temperatures are obtained to decrease from 81 K to 53 K with the increase in Cr addition. Moreover, the phase and lattice parameters were determined from XRD measurements. Based on the refinement of cell parameters done by considering the structural modulation, the Cr addition was confirmed by an increase of the lattice parameter a and decrease of the cell parameter a of the samples in comparison with that of the undoped sample (Cr0). As for the microstructure and element composition analyses on the surface of the samples produced, SEM and EDS measurements were investigated. According to the measurements, not only were the grain sizes of the samples noted to decrease, but also the surface morphology and grain connectivity were obtained to degrade with increase in the

The Successful Incorporation of Nd Into Ba Site of Y0.9Ho0.1Ba2-yNdyCu3O7-δ Bulk Superconductors

“…Besides, this behavior (firstly increase then decrease in c value) can be explained by the fact that the ionic radius of Nd 2+ (143 pm) is slightly smaller compared to Ba 2+ (149 pm), leading to regular expansion of the cell parameter c with the rise of the Nd concentration in the Y-123 up to the certain content value of x=0.100 and y=0.100 beyond which the c axis length begins to shrink quickly. This is consistent with the fact that the Ho 3+ and Nd 2+ ions can be substituted for the Cu 2+ individuals in the crystal structure after the critical value of x=0.100 and y=0.100, supported by the findings of the EDS measurement [27]. In other words, hole filling plays a dominant role in determining the superconductivity of Ho and Nd substituted Y-123s.…”

Effects of Ni Substitution in Bi-2212 Superconductors

“…T c (onset) transition temperatures of the A, B, C, and D samples are found to be about 86.3 K, 81.6 K, 78.7 K, and 75.2 K, respectively (see Table 1). This phenomenon may be dependent on weak links of the superconducting grains, impurity levels and lattice defects of the doped samples [10][11][12][13]. Moreover, roomtemperature resistivity of samples increases with Ni content.…”

The Influence of Postannealing on Structural and Superconducting Properties of Bi-2212 Ceramics

“…Among the high-temperature superconducting materials, the Bi-2212 phase is considered as the most attractive because it has high chemical stability and is relatively easy to synthesize for many technological and industrial applications [1][2][3][4][5][6][7].…”