Superconducting and transport properties of Y$_{3}$Ba$_{5}$Cu$_{8}$O$_{X}$ and Y$_{3}$Ca$_{2}$Ba$_{5}$Cu$_{8}$O$_{x}$ prepared by sol-gel method

The influence of substitution of Ca has been studied using electrical resistivity ($\rho )$, X-ray diffraction (XRD), atomic force microscopy (AFM), energy dispersive analysis (EDX), differential thermal analysis (DTA), thermogravimetric analysis (TGA), Hall coefficient (R$_{ H})$, Hall mobility ($\mu _{H})$ and magnetoresistance measurements. The XRD spectra showed that they almost have the same crystal structure of Y$_{3}$Ca$_{2}$Ba$_{5}$Cu$_{8}$O$_{x}$ as Y$_{3}$Ba$_{5}$Cu$_{8}$O$_{x }$with some impurities peaks. The resistivity measurements were made by the four-probe method. The Y$_{3}$Ba$_{5}$Cu$_{8}$O$_{x }$ and Y$_{ 3}$Ca$_{2}$Ba$_{5}$Cu$_{8}$O$_{x}$ have the highest T$_{c}$-onset at about 92.7 and 86.6 K, respectively. The Hall coefficient R$_{H}$ and Hall mobility $\mu _{H}$ are measurement between 10-300 K temperatures at magnetic field of 0.55 T. The sign of R$_{H}$ and $\mu _{H}$ are positive for two samples which indicate that the conduction is $p$-type for the samples. A small change of normal state resistivity and superconducting transition are observed in the resistivity curve with the magnetic field.