Superconductivity investigation of (Bi, Pb)-2223 added with different nanoferrites and their composites

Abstract In this study, the impact of different types of nanoferrites additions of Zn 0.5 Ni 0.5 Fe 2 O 4 and Ba 0.4 Sr 0.4 Ca 0.2 Fe 12 O 19 nanoparticles and their nanocomposite of (Zn 0.5 Ni 0.5 Fe 2 O 4 ) 0.5 (Ba 0.4 Sr 0.4 Ca 0.2 Fe 12 O 19 ) 0.5 on the structural and normal state resistivity of Bi 1.6 Pb 0.4 Sr 2 Ca 2 Cu 3 O 10 , ((Bi,Pb)-2223) superconducting phase were systematically investigated. The samples were synthesised using high purity oxide powders via a solid-state reaction approach. Based on the Rietveld analysis of x-ray diffraction (XRD) data, the tetragonal structure of (Bi,Pb)-2223 was established to be the predominant phase for all composite samples of the three nano-additions’ contents. However, a little change to the lattice parameters ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>a</mml:mi> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>c</mml:mi> </mml:math> ) was obtained. Furthermore, the small amounts (0.04 wt%) of Ba 0.4 Sr 0.4 Ca 0.2 Fe 12 O 19 and (Zn 0.5 Ni 0.5 Fe 2 O 4 ) 0.5 (Ba 0.4 Sr 0.4 Ca 0.2 Fe 12 O 19 ) 0.5 improved the development of the (Bi,Pb)-2223 phase. The volume fraction of the (Bi,Pb)-2223 phase increased from 86.47% to 88.73% and 88.69%, respectively. Then, it declined to 74.25% and 71.48% upon rising x to 0.40 wt%, respectively, as well as for Zn 0.5 Ni 0.5 Fe 2 O 4 nanoparticles up to 0.40 wt%. SEM images verify the host superconducting matrix’s granular structure for all three nanoadditions up to 0.40 wt%. The existence of three nano additions in the host superconductor matrix is verified by employing energy dispersive x-ray (EDX) and x-ray photoelectron spectroscopy (XPS) analysis. The measurements for the resistivity dependency of temperature presented that, as compared to the pure sample (T c = 108.67 K), the nano-(Zn 0.5 Ni 0.5 Fe 2 O 4 ) x added in the (Bi,Pb)-2223 phase exhibits more negative impact than it is with the other two additions. In contrast, the nano-(Ba 0.4 Sr 0.4 Ca 0.2 Fe 12 O 19 ) x has the highest value of T c with a value of 110.95 K at x = 0.04 wt%. Furthermore, the superconducting transition width (∆T c ) improved for all composite samples except for the sample at x = 0.04 wt%, for Ba 0.4 Sr 0.4 Ca 0.2 Fe 12 O 19 and (Zn 0.5 Ni 0.5 Fe 2 O 4 ) 0.5 (Ba 0.4 Sr 0.4 Ca 0.2 Fe 12 O 19 ) 0.5 which showed the sharpest transition width. This suggests that their addition is anticipated to act as artificial pinning centers and strengthen the coupling between the grains in the (Bi,Pb)-2223 ceramic.