ScholarWorks@성균관대학교

초록

This study investigates the influence of hydroxyapatite (HAp) nanoparticles on the structural and superconducting properties of BPSCCO ceramics synthesized by the solid-state reaction method. HAp nanoparticles, characterized by their rod-like shape and size range of 40–100 nm, are added into the BPSCCO ceramic to enhance flux pinning and improve critical current density (Jc) under applied magnetic fields. In X-ray diffraction (XRD) analysis, the addition of HAp inclusions led to an enhance in lattice parameters, indicating slight lattice strain, while the crystallite size decreased at higher HAp contents. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) confirmed the uniform distribution of HAp nanoparticles on the superconducting grain surfaces, supporting better inter-grain connectivity. Transport and magnetization measurements showed that while the superconducting transition temperature ((Formula presented) ) decreased slightly with increasing HAp content, flux-pinning characteristics improved.The superconducting transition behavior is examined under varying magnetic fields, showing that HAp content notably enhanced the activation energy (U0), particularly for contents of x = 0.002 and x = 0.004 samples. An important increase in the upper critical field (Bc2) is found at lower addi, indicating enhanced vortex pinning. However, excessive content (x ≥ 0.006) led to a decrease in both Jc and Bc2, demonstrating an optimal addition range for achieving maximum superconducting performance. Fourier-transform infrared (FT-IR) and Raman spectroscopy further confirmed the successful integration of HAp nanoparticles into the BPSCCO ceramics. These results exhibit that HAp nanoparticles assist as successful flux pinning centers, improving the superconducting properties of BPSCCO up to a certain doping threshold, offering potential for the development of high-performance superconducting materials.

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