The investigation of the effects of partial Dy substitution for Y on YBaCuO (123) superconducting system

In this study, the effect of partial Dy substitution for Y on YBaCuO (123) superconductor prepared by solid state reaction method was investigated using XRD, magnetization and magnetic susceptibility measurements. From X-ray diffraction method, it was determined that the samples were in Y-123 orthorhombic structure and the lattice parameters increased with increasing Dy doping. This increment was attributed to the relatively larger ionic radius of Dy (1.027 A ? ) comparing to that of Y atom (1.019 A ? ). It was observed that in M-H loops with larger field (Hmax=20000 Oe) the paramagnetic behavior were dominated by diamagnetic behavior and it was observed that magnetization had positive values. It was also observed that paramagnetic behavior was more significant with increasing Dy doping. It was determined that the sample with x=0 Dy doping had the highest critical current density in maximum (Jc,max) as a function of magnetic field for T=5, 20 and 77 K. However, the sample with having the highest critical current density was one of having x=0.6 Dy doping for T=5 K (9645 A/cm2). In addition, at larger magnetic fields it was found that the sample with x=0.6 Dy doping had the highest critical current density for T=20 K and 77 K. It was determined that the critical transition temperature (Tc) from magnetization (M-H) and AC susceptibility measurements as a function of temperature was increased for the doping of x=0.2-0.6 Dy as comparing to the pure sample (x=0 doping). The temperature dependence of intergranular critical current densities (Jcm-T) of x=0 and x=0.6 Dy doped samples were determined by using AC susceptibility data. It was observed that the both samples had almost same Jcm-T change. It was observed that critical current densities of the samples with x=0 and x=0.6 Dy doping obtained from AC susceptibility values for T=77 K and Hac=1 Oe were in an agreement with the critical current densities obtained from M-H curves for almost zero field for T=77 K.Key Words: YBaCuO (123) Superconductor, Dy Doping, M-H Hysteresis Loop, Critical Current Density, AC Susceptibility