STRUCTURAL AND ELECTROMAGNETIC PROPERTIES OF BI-SR-CA-CU-NI-O SINGLE-CRYSTALS

The structural and physical properties have been investigated in Bi2Sr2Ca1Cu2-xNixO8+delta (X=0, 0.02 and 0.04) single crystals. Powder X-ray diffraction pattern and high resolution electron microscope image confirm all of the single crystals to be of Bi(2212) phase with a superstructure along the b-axis. Although the superconducting transition temperature and the ratio of rho(b)/rho(a) decrease linearly with Ni concentration, we couldn't observe any structural change in single crystals by high resolution image and electron diffraction measurement. Magnetic hysteresis curves for X=0 and 0.04 at 35 K are the same each other. These results suggest that Ni atoms don't form clusters but distribute uniformly in CuO2 plane.