SrTiO_(3)(001) vicinal substrates of miscut 1°, 3°, and 6° toward the (001) plane were annealed at 800-1000°C in pure flowing O_(2) for 6h and examined by atomic force microscopy. The high temperat...SrTiO_(3)(001) vicinal substrates of miscut 1°, 3°, and 6° toward the (001) plane were annealed at 800-1000°C in pure flowing O_(2) for 6h and examined by atomic force microscopy. The high temperature annealed vicinal SiTiO_(3)(001) displayed arrays of straight steps and smooth terraces. The step heights vary from about 2 to 6 unit cell depending on the annealing temperatures. At 1000°C, step bunching becomes obvious. The height steps of 1 unit cell are difficult to be observed by our atomic force microscopy. The YBa2Cu3O7-δ thin film grows epitaxially on the step-terrace surface with c-axis orientation by magnetron sputtering in the two-dimensional island mode. Prospect of step-flow growth is being discussed.展开更多
We report on the observation of the Josephson effect on the newly discovered superconductor MgB_(2) with the breakjunction technique. Similar to conventional superconductors, the I-V curve can be fitted with the resis...We report on the observation of the Josephson effect on the newly discovered superconductor MgB_(2) with the breakjunction technique. Similar to conventional superconductors, the I-V curve can be fitted with the resistively shunted junction model including the noise effect, and a large characteristic voltage V_(c)= I_(c)R_(N) = 9.6meV was obtained. The energy gap determined by the Ambegaokar-Baratoff relation with the fitted Vc is very consistent with the Bardeen-Cooper-Schrieffer weak-coupling value. Our result implies that the superconductor MgB_(2) is a promising material for Josephson device applications.展开更多
We report temperature-dependent behavior of the zero bias tunneling conductance(ZBTC),derived from tun neling spectroscopies on as-grown Bi_(2)Sr_(2)CaCu_(2)O_(8+δ)(Bi2212)single crystals taken with evaporated Zn and...We report temperature-dependent behavior of the zero bias tunneling conductance(ZBTC),derived from tun neling spectroscopies on as-grown Bi_(2)Sr_(2)CaCu_(2)O_(8+δ)(Bi2212)single crystals taken with evaporated Zn and Pb planar junctions.At Tc the measured ZBTC shows a kink which gives an in situ measure of the superconducting transition temperature(T_(c)).Below T_(c),the T^(2)dependence of the ZBTC has been observed repeatedly as a new evidence of the d-wave symmetry in Bi2212.展开更多
Laser molecular beam epitaxy(laser MBE)technique was utilized to grow the barium titanate(BaTiO_(3),BTO)thin films on SrTiO_(3)(100)substrates.The surface morphology of the BaTiO_(3) thin films was studied by atomic f...Laser molecular beam epitaxy(laser MBE)technique was utilized to grow the barium titanate(BaTiO_(3),BTO)thin films on SrTiO_(3)(100)substrates.The surface morphology of the BaTiO_(3) thin films was studied by atomic force microscopy(AFM).Two-and three-dimensional AFM images were obtained.The root mean square surface roughness,the height profile,the histogram and the bearing ratio of the height distributions for the BaTiO_(3) thin films were analyzed in detail.The results indicate that the laser MBE thin films exhibit an atomically smooth surface.展开更多
文摘SrTiO_(3)(001) vicinal substrates of miscut 1°, 3°, and 6° toward the (001) plane were annealed at 800-1000°C in pure flowing O_(2) for 6h and examined by atomic force microscopy. The high temperature annealed vicinal SiTiO_(3)(001) displayed arrays of straight steps and smooth terraces. The step heights vary from about 2 to 6 unit cell depending on the annealing temperatures. At 1000°C, step bunching becomes obvious. The height steps of 1 unit cell are difficult to be observed by our atomic force microscopy. The YBa2Cu3O7-δ thin film grows epitaxially on the step-terrace surface with c-axis orientation by magnetron sputtering in the two-dimensional island mode. Prospect of step-flow growth is being discussed.
基金Supported by the State Key Program for Basic Research of Chinathe National Center for Research&Development on Superconductivity.
文摘We report on the observation of the Josephson effect on the newly discovered superconductor MgB_(2) with the breakjunction technique. Similar to conventional superconductors, the I-V curve can be fitted with the resistively shunted junction model including the noise effect, and a large characteristic voltage V_(c)= I_(c)R_(N) = 9.6meV was obtained. The energy gap determined by the Ambegaokar-Baratoff relation with the fitted Vc is very consistent with the Bardeen-Cooper-Schrieffer weak-coupling value. Our result implies that the superconductor MgB_(2) is a promising material for Josephson device applications.
基金Supported by a grant for State Key Program for Basic Research of China,and the National Center for Research&Development on Superconductivity.
文摘We report temperature-dependent behavior of the zero bias tunneling conductance(ZBTC),derived from tun neling spectroscopies on as-grown Bi_(2)Sr_(2)CaCu_(2)O_(8+δ)(Bi2212)single crystals taken with evaporated Zn and Pb planar junctions.At Tc the measured ZBTC shows a kink which gives an in situ measure of the superconducting transition temperature(T_(c)).Below T_(c),the T^(2)dependence of the ZBTC has been observed repeatedly as a new evidence of the d-wave symmetry in Bi2212.
基金Supported by the National Natural Science Foundation of China under Grant Nos.59392800 and 69437101the Chinese Academy of Sciences,the National Superconducting Research Center,and the Research Grant No.94-189 RG/PHYS/AS of the Third World Academy of Sciences.
文摘Laser molecular beam epitaxy(laser MBE)technique was utilized to grow the barium titanate(BaTiO_(3),BTO)thin films on SrTiO_(3)(100)substrates.The surface morphology of the BaTiO_(3) thin films was studied by atomic force microscopy(AFM).Two-and three-dimensional AFM images were obtained.The root mean square surface roughness,the height profile,the histogram and the bearing ratio of the height distributions for the BaTiO_(3) thin films were analyzed in detail.The results indicate that the laser MBE thin films exhibit an atomically smooth surface.
