GROWTH AND CHARACTERIZATION OF LA2-XSRXCUO4-DELTA BULK SINGLE-CRYSTALS

Single crystals of La2-xSrxCuO4-delta (x=0, x=0.10, x=0.15 and x=0.20) were grown in oxygen atmosphere using the Travelling Solvent Floating Zone (TSFZ) method. The as grown rods were analyzed by Electron Probe Micro Analysis (EPMA), x-ray diffraction and neutron diffraction techniques. EPMA results showed the correct phase with homogeneous strontium distribution. Neutron diffraction revealed single crystalline grains with sizes up to 200 mm(3). The onset of the superconducting transition temperatures of crystals with composition La1.90Sr0.10CuO4-delta and La1.85Sr0.15CuO4-delta determined from ac susceptibility were 25K and 35K with 90% of the transition within 3K. A full report is given on preparation method of the starting materials and growth parameters. Additionally, single crystals of La2NiO4, Nd2CuO4 and Sm2CuO4 were grown. Diamond saw and spark-erosion were used to separate the crystals from as grown boules. Experience with spark-erosion technique to shape samples for physical measurements is reported.