We have developed a simple sintering system to prepare the yttria-stabilized-zirconia(YSZ)bicrystals.Grain-boundary junctions made from the epitaxial YBa_(2)Cu_(3)O_(7-δ) films on the bicrystal substrates demonstrate...We have developed a simple sintering system to prepare the yttria-stabilized-zirconia(YSZ)bicrystals.Grain-boundary junctions made from the epitaxial YBa_(2)Cu_(3)O_(7-δ) films on the bicrystal substrates demonstrated Josephson behavior.Using new square washer design,single-level magnetometer of dc superconducting quantum interference.device(SQUID)has been fabricated.Owing to the flux focusing effect of the large washer,the magnetic field sensitivity of the devices has been enhanced.The magnetic field resolution of the magnetometer is IpT/Hz^(1/2) at 10Hz,and increases to 3pT/Hz^(1/2) at 1Hz at 77K.展开更多
We report the results of femtosecond spectroscopy studies on YBa_(2)Cu_(3)O_(7-x )and PrBa_(2)Cu_(3)O_(7-x )(x=0.1)epitaxial thin films at room temperature.The transient reSectivity signals ΔR(t)in the samples are co...We report the results of femtosecond spectroscopy studies on YBa_(2)Cu_(3)O_(7-x )and PrBa_(2)Cu_(3)O_(7-x )(x=0.1)epitaxial thin films at room temperature.The transient reSectivity signals ΔR(t)in the samples are consistent with a band filliitg model.The relaxation times of ΔR(t)in YBa_(2)Cu_(3)O_(7-x ) increase from less th&n 100 fs to more than Ips with increasing x and with substitution of Pr for Y.These results reveal that in high Tc superconductors decrease of carrier concentration slows down the carrier-phonon coupling.展开更多
The study of“irreversibility line”and magnetization curves of a YBCO superconductor prepared by melt-textured growth method is presented.It is shown'that the temperature T above whjich the magnetization is rever...The study of“irreversibility line”and magnetization curves of a YBCO superconductor prepared by melt-textured growth method is presented.It is shown'that the temperature T above whjich the magnetization is reversible can be identified with the temperature above which J_(c) is negligible,demonstrating the.Yeshurun and Malozemoff's theory about“irreversibility line”.展开更多
The structural,magnetic and superconducting properties of the Tl_(2)Ba_(2)(Ca_(1-x)Mg_(x))_(2)Cu_(3)O_(y)system with x=0,0.05,0.1,0.15,0.2,0.3,0.4,0.5 were studied.Replacement of calcium by magnesium depresses Tc from...The structural,magnetic and superconducting properties of the Tl_(2)Ba_(2)(Ca_(1-x)Mg_(x))_(2)Cu_(3)O_(y)system with x=0,0.05,0.1,0.15,0.2,0.3,0.4,0.5 were studied.Replacement of calcium by magnesium depresses Tc from 116.3K(x=0)to 93.3K(x=0.5).The critical current also decreases with increasing x.展开更多
The structure,magnetic,and superconducting properties of the (Tl_(1-x)Al_(x))2Ba_(2)Ca_(2)Cu_(3)O_(y) with x=0.05,0.1,0.15,0.2 were studied.The T_(c)^(R=0) depends on whether the sample has a 222S phase structure or h...The structure,magnetic,and superconducting properties of the (Tl_(1-x)Al_(x))2Ba_(2)Ca_(2)Cu_(3)O_(y) with x=0.05,0.1,0.15,0.2 were studied.The T_(c)^(R=0) depends on whether the sample has a 222S phase structure or has a 2212 phase structure.The magnetic properties in low field were measured and discussed.展开更多
基金Supported by the National Research and Development Center for SuperconductivityFEUYT of State Educational Commission of China.
文摘We have developed a simple sintering system to prepare the yttria-stabilized-zirconia(YSZ)bicrystals.Grain-boundary junctions made from the epitaxial YBa_(2)Cu_(3)O_(7-δ) films on the bicrystal substrates demonstrated Josephson behavior.Using new square washer design,single-level magnetometer of dc superconducting quantum interference.device(SQUID)has been fabricated.Owing to the flux focusing effect of the large washer,the magnetic field sensitivity of the devices has been enhanced.The magnetic field resolution of the magnetometer is IpT/Hz^(1/2) at 10Hz,and increases to 3pT/Hz^(1/2) at 1Hz at 77K.
基金Supported by the National Center for Research and Development on Superconductivity of China.
文摘We report the results of femtosecond spectroscopy studies on YBa_(2)Cu_(3)O_(7-x )and PrBa_(2)Cu_(3)O_(7-x )(x=0.1)epitaxial thin films at room temperature.The transient reSectivity signals ΔR(t)in the samples are consistent with a band filliitg model.The relaxation times of ΔR(t)in YBa_(2)Cu_(3)O_(7-x ) increase from less th&n 100 fs to more than Ips with increasing x and with substitution of Pr for Y.These results reveal that in high Tc superconductors decrease of carrier concentration slows down the carrier-phonon coupling.
文摘The study of“irreversibility line”and magnetization curves of a YBCO superconductor prepared by melt-textured growth method is presented.It is shown'that the temperature T above whjich the magnetization is reversible can be identified with the temperature above which J_(c) is negligible,demonstrating the.Yeshurun and Malozemoff's theory about“irreversibility line”.
文摘The structural,magnetic and superconducting properties of the Tl_(2)Ba_(2)(Ca_(1-x)Mg_(x))_(2)Cu_(3)O_(y)system with x=0,0.05,0.1,0.15,0.2,0.3,0.4,0.5 were studied.Replacement of calcium by magnesium depresses Tc from 116.3K(x=0)to 93.3K(x=0.5).The critical current also decreases with increasing x.
文摘The structure,magnetic,and superconducting properties of the (Tl_(1-x)Al_(x))2Ba_(2)Ca_(2)Cu_(3)O_(y) with x=0.05,0.1,0.15,0.2 were studied.The T_(c)^(R=0) depends on whether the sample has a 222S phase structure or has a 2212 phase structure.The magnetic properties in low field were measured and discussed.
