Crystal structure and magnetic properties of nano-particles BSCNGCO superconductors at room-temperature

ABSTRACT: Synthesis of nano-particles Bi2Sr2(Ca1,5Nd0,25Gd0,25)Cu3Oz (BSCNGCO) superconductors has been successfully done by the wet mixing method. The aim of the study was to produce nanoparticles of BSCNGCO superconductors and study magnetic properties at room temperature. In this research, the raw material used in the formation of BSCNGCO superconductors is Bi2O3 (99.9%), SrCO3 (99.9%), CaCO3 (99.9%), CuO (99.9%), Nd2O3 (99.9%) and Gd2O3 (99.9%). The synthesis process was conducted by added with HNO3 and mixing by a magnetic stirrer to obtain a homogeneous solution, then continued with the calcination process at 450oC for 2 hours and 600oC for 1 hour. The sintering process is done at 830oC with a variation of time, that is 10, 20 and 30 minutes. The result of XRD characterization is dominated by BSCNGCO with 2223 phases and BSCNGCO with 2212 phases, but there are still impurities in each sample such as Bi2CuO4 and Bi2O2.7. The addition of sintering time in 10, 20 and 30 minutes resulted in the addition of fractional volume values of BSCNGCO with 2223 phases, respectively 42.39%, 47.85%, and 49.42%. In contrast, the fraction of the phase volume of impurities (Bi2CuO4, BSCNGCO with 2212 phases, Bi2O2,7) decreases with the addition of sintering time. From the results of TEM morphology and calculations using the Scherrer equation, we can determine the particle size of sample superconductors. The addition of sintering time in 10, 20 and 30 minutes resulted in increased particle size, respectively 25.61 nm, 26.10 nm and 30.08 based on calculations using the Sherrer equation. While the calculations using the ImageJ program of the TEM results of 0.2 nm and 0.5 nm, for the sintering time of 10 and 20 minutes respectively. The results of the VSM characterization of the sample exhibit ferromagnetic properties at room temperature. The addition of sintering time causes the saturation magnetization (Ms), a remanent magnetization (Mr) and coercive force (Hc) values to decrease. Samples of superconductors with sintering time of 10 and 20 minutes showed Ms values of 0.155 emu/g and 0.157 emu/g, Mr values of 0.012 emu/g and 0.011 emu/g, Hc values of 528.623 Oe and 473.327 Oe, respectively. Keywords: wet-mixing, superconductor, XRD, TEM, VSM, nanoparticles, ferromagnetic