Oxide transistor is the basic device to construct the oxide electronic circuit that is the backing to develop integrated oxide electronics with high efficiency and low power consumption.By growing the perovskite oxide...Oxide transistor is the basic device to construct the oxide electronic circuit that is the backing to develop integrated oxide electronics with high efficiency and low power consumption.By growing the perovskite oxide integrated layers and tailoring them to lead semiconducting functions at their interfaces,the development of oxide transistors may be able to perform.We realize a kind of p-i-n type integrated layers consisting of an n-type cuprate superconductor,p-type colossal magnetoresistance manganite,and a ferroelectric barrier(i).From this,bipolar transistors were fabricated at the back-to-back p-i-n junctions,for which the Schottky emission and p-n junction barriers,as well as the ferroelectric polarization,were integrated into the interfaces to control the transport properties;a preliminary but distinct current gain greater than 1.6 at input current of microampers order was observed.These results present a real possibility to date for developing bipolar all perovskite oxide transistors.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
La_(2-x)Sr_(x)Cu_(l+y)O_(4)(LSCO)thin films sputtered from a Cu-rich target on a LaAlO_(3) substrate showed a columnar structure.The columnar grains penetrated the full thickness of the film,nucleating at the substrat...La_(2-x)Sr_(x)Cu_(l+y)O_(4)(LSCO)thin films sputtered from a Cu-rich target on a LaAlO_(3) substrate showed a columnar structure.The columnar grains penetrated the full thickness of the film,nucleating at the substrate surface defects.Transmission electron microscopy revealed two kinds of lattice images:one with a lattice spacing of 0.66 nm and the other with a spacing of 0.61 nm.The 0.66 nm spacing denotes a c-axis oriented LSCO film matrix.The 0.61 nm spacing has two categories:one with short white dashes,the phase of which is not yet identified,the other with no additional structure,which could correspond to the c-axis deviated LSCO.展开更多
Bi_(2)Sr_(2-x)LaxCu_(1)O_(6+δ)(La-2201)thin films were successfully prepared on(100)SrTiO_(3) and(100)LaAIO_(3) substrates by in-situ dc-magnetron sputtering process.A series compensated 2201 targets of La^(3+)substi...Bi_(2)Sr_(2-x)LaxCu_(1)O_(6+δ)(La-2201)thin films were successfully prepared on(100)SrTiO_(3) and(100)LaAIO_(3) substrates by in-situ dc-magnetron sputtering process.A series compensated 2201 targets of La^(3+)substitution contents for Sr^(2+)were studied for growing 2201 phase thin films.The superconducting zero resistance temperature T_(c,0) reached 19K.X-ray diffraction analyses showed that films oriented with c-axis perpendicular to the substrate surface and their lattice parameters are around 2.43-2.46nm.Ф-scan and rocking curve show a good epitaxial growth and crystallisation of the films.展开更多
Measurement and characterization were carried out on Cu-doped and undoped La_(2)CuO_(4+δ) samples prepared under the same conditions.The magnetization measurement on the Cu-doped La_(2)CuO_(4+δ) sample shows coexist...Measurement and characterization were carried out on Cu-doped and undoped La_(2)CuO_(4+δ) samples prepared under the same conditions.The magnetization measurement on the Cu-doped La_(2)CuO_(4+δ) sample shows coexistence of long-range antiferromagnetic order and superconductivity.A stripe-like structure was observed at room temperature on the ab-plane of Cu-doped La_(2)CuO_(4+δ) sample by transmission electron microscope.While for the undoped La_(2)CuO_(4+δ) sample no such behavior or structure feature was found.In this letter,these phenomena were discussed in terms of phase separation.展开更多
Bicvystal Josephson junctions and direct current superconducting quantum inter ference devices(dc sQUIDs)were prepared on YBa_(2)Cu_(3)O_(7)(YBCO)thin films deposited on yttrium stabilized ZrO_(2) bicrystal substrates...Bicvystal Josephson junctions and direct current superconducting quantum inter ference devices(dc sQUIDs)were prepared on YBa_(2)Cu_(3)O_(7)(YBCO)thin films deposited on yttrium stabilized ZrO_(2) bicrystal substrates.The critical current densities J_(c)~2×10^(6)/cm^(2) for YBCO thin filmand(1-3)×10^(3)A/cm^(2) at boundaries were obtained at 77 K.For YBCO Josephson junctionmade on 28° misorientated boundary,the Shapiro steps were observed.The dc SQUID was madeon the 32° misorientated boundary junctions,which consisted of 40×40 m of loop and 2000×2000 pn planar superconductive flu.r focuser.The zoltage modulation depth of this SQUID was6 p.V,and the magnetic field sensitivity was estimated to be~2 pT/√Hz from the measurednoise level.展开更多
Many scientists hypothesized that the presence of oxygen is necessary for the formation and stabilization of the metastable high Tc A15 Nb3Ge phase in Nb-Ge films.In our previous work we proposed that a certain amount...Many scientists hypothesized that the presence of oxygen is necessary for the formation and stabilization of the metastable high Tc A15 Nb3Ge phase in Nb-Ge films.In our previous work we proposed that a certain amount of Nb_(5)Ge_(3) may play a role in stabilizing the high T_(c) A15 phase.New experimental results of induction measurement on the Nb-Ge films support our proposal.展开更多
The magnetic and electric properties of polycrystalline(La_(0.7)Tb_(0.3))_(2/3)Ca_(l/3)MnO_(3)were investigated.A spin glass-paramagnetic transition and metal-insulator transition were observed near 45K,and there exis...The magnetic and electric properties of polycrystalline(La_(0.7)Tb_(0.3))_(2/3)Ca_(l/3)MnO_(3)were investigated.A spin glass-paramagnetic transition and metal-insulator transition were observed near 45K,and there exists continuous volume change in the range of measured temperature.At 60 K,a large anisotropic magnetostriction and a volume magnetostriction correspond to an isotropic colossal magnetoresistance(CMR)with the magnitude of more than 40%at an applied field of±0.1 T.Our results demonstrate that the transition is of second-order in nature and CMR could be caused by spin-charge coupling in this compound.展开更多
基金Supported by the Knowledge Innovation Program of the Chinese Academy of Sciences under Grant No KJCX2YW-W16the National Basic Research Program of China(2010CB630700)the National Natural Science Foundation of China(10904116).
文摘Oxide transistor is the basic device to construct the oxide electronic circuit that is the backing to develop integrated oxide electronics with high efficiency and low power consumption.By growing the perovskite oxide integrated layers and tailoring them to lead semiconducting functions at their interfaces,the development of oxide transistors may be able to perform.We realize a kind of p-i-n type integrated layers consisting of an n-type cuprate superconductor,p-type colossal magnetoresistance manganite,and a ferroelectric barrier(i).From this,bipolar transistors were fabricated at the back-to-back p-i-n junctions,for which the Schottky emission and p-n junction barriers,as well as the ferroelectric polarization,were integrated into the interfaces to control the transport properties;a preliminary but distinct current gain greater than 1.6 at input current of microampers order was observed.These results present a real possibility to date for developing bipolar all perovskite oxide transistors.
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 Chinese National Center for Research and Development on Superconductivity。
文摘La_(2-x)Sr_(x)Cu_(l+y)O_(4)(LSCO)thin films sputtered from a Cu-rich target on a LaAlO_(3) substrate showed a columnar structure.The columnar grains penetrated the full thickness of the film,nucleating at the substrate surface defects.Transmission electron microscopy revealed two kinds of lattice images:one with a lattice spacing of 0.66 nm and the other with a spacing of 0.61 nm.The 0.66 nm spacing denotes a c-axis oriented LSCO film matrix.The 0.61 nm spacing has two categories:one with short white dashes,the phase of which is not yet identified,the other with no additional structure,which could correspond to the c-axis deviated LSCO.
文摘Bi_(2)Sr_(2-x)LaxCu_(1)O_(6+δ)(La-2201)thin films were successfully prepared on(100)SrTiO_(3) and(100)LaAIO_(3) substrates by in-situ dc-magnetron sputtering process.A series compensated 2201 targets of La^(3+)substitution contents for Sr^(2+)were studied for growing 2201 phase thin films.The superconducting zero resistance temperature T_(c,0) reached 19K.X-ray diffraction analyses showed that films oriented with c-axis perpendicular to the substrate surface and their lattice parameters are around 2.43-2.46nm.Ф-scan and rocking curve show a good epitaxial growth and crystallisation of the films.
基金Supported by the National Center for Research and Developments on Superconductivity of China.
文摘Measurement and characterization were carried out on Cu-doped and undoped La_(2)CuO_(4+δ) samples prepared under the same conditions.The magnetization measurement on the Cu-doped La_(2)CuO_(4+δ) sample shows coexistence of long-range antiferromagnetic order and superconductivity.A stripe-like structure was observed at room temperature on the ab-plane of Cu-doped La_(2)CuO_(4+δ) sample by transmission electron microscope.While for the undoped La_(2)CuO_(4+δ) sample no such behavior or structure feature was found.In this letter,these phenomena were discussed in terms of phase separation.
基金Supported by the National Research and Development Cent er for Superconductivity.
文摘Bicvystal Josephson junctions and direct current superconducting quantum inter ference devices(dc sQUIDs)were prepared on YBa_(2)Cu_(3)O_(7)(YBCO)thin films deposited on yttrium stabilized ZrO_(2) bicrystal substrates.The critical current densities J_(c)~2×10^(6)/cm^(2) for YBCO thin filmand(1-3)×10^(3)A/cm^(2) at boundaries were obtained at 77 K.For YBCO Josephson junctionmade on 28° misorientated boundary,the Shapiro steps were observed.The dc SQUID was madeon the 32° misorientated boundary junctions,which consisted of 40×40 m of loop and 2000×2000 pn planar superconductive flu.r focuser.The zoltage modulation depth of this SQUID was6 p.V,and the magnetic field sensitivity was estimated to be~2 pT/√Hz from the measurednoise level.
文摘Many scientists hypothesized that the presence of oxygen is necessary for the formation and stabilization of the metastable high Tc A15 Nb3Ge phase in Nb-Ge films.In our previous work we proposed that a certain amount of Nb_(5)Ge_(3) may play a role in stabilizing the high T_(c) A15 phase.New experimental results of induction measurement on the Nb-Ge films support our proposal.
基金the China Post-doctoral Science Foundation,and the National Natural Science Foundation of China under Grant No.59392800-2.
文摘The magnetic and electric properties of polycrystalline(La_(0.7)Tb_(0.3))_(2/3)Ca_(l/3)MnO_(3)were investigated.A spin glass-paramagnetic transition and metal-insulator transition were observed near 45K,and there exists continuous volume change in the range of measured temperature.At 60 K,a large anisotropic magnetostriction and a volume magnetostriction correspond to an isotropic colossal magnetoresistance(CMR)with the magnitude of more than 40%at an applied field of±0.1 T.Our results demonstrate that the transition is of second-order in nature and CMR could be caused by spin-charge coupling in this compound.
