Microtubule-associated proteins (MAPs) are important proteins in cells. They can regulate the organization, dynamics and function of microtubules. We measure the binding force between microtubule and a new plant MAP...Microtubule-associated proteins (MAPs) are important proteins in cells. They can regulate the organization, dynamics and function of microtubules. We measure the binding force between microtubule and a new plant MAP, i.e. AtMAP65-1, by dual-optical tweezers. The force is obtained to be 14.6 ± 3.5 pN from the data statistics and analysis. This force measurement is helpful to understand the function and mechanism of MAPs from the mechanical point of view and lays the groundwork for future measurements of the mechanical properties of other biological macro-molecules.展开更多
Aligned carbon nanotube (CNRT) films exhibit excellent electron emission properties at very low fields. This has been attributed to the high aspect ratio of CNTs, I.e. Their emitting surface can have high local field ...Aligned carbon nanotube (CNRT) films exhibit excellent electron emission properties at very low fields. This has been attributed to the high aspect ratio of CNTs, I.e. Their emitting surface can have high local field due to geometrical enhancement. It is found that a new mechanism can be responsible for the enhancement of the local field on the emitting surface of CNTs. This results from the space charge in the vacuum gap, which is readily generated due to the high emission current density of CNTs. Details are given of both experimental and theoretical studies of this effect. The mechanism also accounts for the distinct nonlinearity in Fowler-Nordheim plots often observed with CNTs. The implication of the technical application of our findings is also included.展开更多
The lanthanum strontium aluminium tantalum oxide(LSAT)crystal is grown by means of a floating or pulling method.Its optical transmittance,refractive indices in visible and near-infrared areas and its dispersion curve ...The lanthanum strontium aluminium tantalum oxide(LSAT)crystal is grown by means of a floating or pulling method.Its optical transmittance,refractive indices in visible and near-infrared areas and its dispersion curve are reported.The transparence range of LSAT is from 0.45 to 4.2μm and its refractive index is 2.0244.展开更多
A way to determine some important etching parameters in the step fabrication for highTc step-edge Josephson junctions is described based on an analysis of the dynamics of the etching process.The optimum thickness of t...A way to determine some important etching parameters in the step fabrication for highTc step-edge Josephson junctions is described based on an analysis of the dynamics of the etching process.The optimum thickness of the etch mask is defined with negligible recession of the mask edge during the etch.Under this condition,the equilibrium angle of the steps etched on the SrTiO_(3)(STO)substrate with an Nb mask has been calculated to be about 76°.With optimized mask thickness,its sharp sidewall and straight edge,high-quality steps on STO substrates with step height from 200-300 nm and step angle above 70°are made.Josephson junctions and dc-SQUIDs with high reproducibility and less parameter scatter are obtained on the step substrates.展开更多
The Trapping force on Rayleigh particles in an optical tweezers system with an oil immersion objective is calculated by an electromagnetic model.The results indicate that the stability of particles trapped will be aff...The Trapping force on Rayleigh particles in an optical tweezers system with an oil immersion objective is calculated by an electromagnetic model.The results indicate that the stability of particles trapped will be affected by spherical aberration,which is caused by refractive difference between objective oil and water solution,when the specimen manipulated is suspended in a water solution.The trapping force and depth of potential well will decrease and the minimum of laser power for ensuring the stability of particles trapped will increase with the enhancing trapping depth.展开更多
The new superconductor MgB_(2) has been prepared by two ways: high pressure and ambient pressure synthesis. Their superconducting properties were measured and compared. It is found that the sample prepared by high pre...The new superconductor MgB_(2) has been prepared by two ways: high pressure and ambient pressure synthesis. Their superconducting properties were measured and compared. It is found that the sample prepared by high pressure is much denser than that prepared under ambient pressure. Accordingly the high pressure sample has a very narrow transition width and a much higher bulk critical current density.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
Resistive transitions of the new superconductor MgB_(2) are carried out under magnetic fields from 0 to 8 T.It is found that the irreversibility field Hirr(T)and the upper critical field Hc2(T)obtained are very close ...Resistive transitions of the new superconductor MgB_(2) are carried out under magnetic fields from 0 to 8 T.It is found that the irreversibility field Hirr(T)and the upper critical field Hc2(T)obtained are very close to those determined in the magnetic measurement.By using the Arrhenius activation lawρ=ρ0exp(-U/kBT),the activation barrier U has been determined by the low dissipation part of R(T)curves.It is found that U■kBT manifests a very weak thermal activation and thermal fluctuation effect.This may further indicate that the flux dynamics near Hirr(T)is induced by strong quantum fluctuation and tunneling of vortices.展开更多
Structural,magnetic,and transport properties of perovskite La_(2/3)Ca_(1/_3)Mn_(1-x)Si_(x)O_(3)(x=0,0.025,0.05)have been studied.The incorporation of Si decreases the overall resistivity,but obviously increases the Cu...Structural,magnetic,and transport properties of perovskite La_(2/3)Ca_(1/_3)Mn_(1-x)Si_(x)O_(3)(x=0,0.025,0.05)have been studied.The incorporation of Si decreases the overall resistivity,but obviously increases the Curie temperature(TC),metal-insulator transition temperature(TP),and the magnetoresistance ratio MR(defined as[R(0)-R(H)]/R(0))near room temperature.Comparing with La_(2/3)Ca_(1/_3)MnO_(3)the TC,TP,and MR of the sample with x=0.05 increase by 30,45K,and 20%,respectively.Lattice effects may play a more important role than the magnetic dilution in the case of low Si substitution.展开更多
The linear expansion of Zr_(48)Nb_(8)Cu_(14)Ni_(12)Be_(18) bulk metallic glass(BMG)with excellent glass forming ability and high thermal stability is investigated by a dilatometry method.The average expansion coeffici...The linear expansion of Zr_(48)Nb_(8)Cu_(14)Ni_(12)Be_(18) bulk metallic glass(BMG)with excellent glass forming ability and high thermal stability is investigated by a dilatometry method.The average expansion coefficient is α TG=1.04 × 10^(-5) K^(-1)(300-656 K)for the BMG and α TG=1.11 × 10^(-5) K^(-1)(356~890 K)for the crystallized alloy.The Mie potential as well as the equation of state of the BMG and its corresponding crystallized state are determined from the thermal expansion and ultrasonic data,and the differences among them are phenomenologically explained.展开更多
A series of squarylium cyanine dyes with different substituents were synthesized and the third-order optical nonlinearities of their ground and excited states were investigated by backward degenerate four-wave-mixing....A series of squarylium cyanine dyes with different substituents were synthesized and the third-order optical nonlinearities of their ground and excited states were investigated by backward degenerate four-wave-mixing.For the ground state,the molecular hyperpolarizabilityγg increases with the red-shift of the absorption peakλabmax,of the squaraine with different substituents,whereas for the excited-state molecular hyperpolarizabilityγe,the nonlinear enhancementγe/γg decreases,which may indicate that in the excited state the electron accepting-donating ability of different substituents changes in the reverse order compared with the order in the ground state.展开更多
We fabricated a new type of two-dimensional photonic crystal slab filter. The resonant cavities were directly put into the waveguide arms. The optical transmissions of the filters were measured and the results show th...We fabricated a new type of two-dimensional photonic crystal slab filter. The resonant cavities were directly put into the waveguide arms. The optical transmissions of the filters were measured and the results show that the optimized two-channel filters give good intensity distribution at the output ports of the waveguide. A minimum wavelength spacing of 5 nm of the filter outputs is realized by accurately controlling the size of the resonant cavities.展开更多
Colloidal photonic crystal heterostructures, composed of two opaline photonic crystal films of silica spheres with different diameters, are fabricated by a two-step spin-coating method. Scanning electron microscopy (...Colloidal photonic crystal heterostructures, composed of two opaline photonic crystal films of silica spheres with different diameters, are fabricated by a two-step spin-coating method. Scanning electron microscopy (SEM) and UV-vis spectrophotometer are used to characterize the heterostructures. The SEM images show good ordering of the two-layer colloidal crystals constituting the heterostructures. The transmission spectra measured from the (111) plane in the heterostructure show that the composite colloidal photonic crystals have double photonic stop bands. Furthermore, when the sizes of the silica spheres used for fabricating the composite photonic crystal are slightly different, the transmission spectrum shows that the composite photonic crystals have more extended bandgap than that of the individual photonic crystals due to partial overlapping of its two photonic stop bands.展开更多
Infrared absorption spectra of La0.67-xPrxCa0.33MnO3 (x= 0, 0.18 and 0.36) are experimentally studied in the temperature range 20 -300K. Absorption peak splitting corresponding to the stretching oscillation of the M...Infrared absorption spectra of La0.67-xPrxCa0.33MnO3 (x= 0, 0.18 and 0.36) are experimentally studied in the temperature range 20 -300K. Absorption peak splitting corresponding to the stretching oscillation of the Mn-O bond, together with a shift of peak position, is observed below the Curie temperature. These features weaken and even disappear as the samples are warmed up to the Curie temperature, which indicates that this anomaly may be a result of phase separation in the compounds.展开更多
This paper reports that the detection to the protein in microarray format is carried out by oblique-incidence reflectivity difference (OI-RD) analysis without any labelling agents. The OI-RD intensities not only dep...This paper reports that the detection to the protein in microarray format is carried out by oblique-incidence reflectivity difference (OI-RD) analysis without any labelling agents. The OI-RD intensities not only depend on the protein structure, but also vary with the protein concentration. The results indicate that this method should have potential application in detection of biochemical processes. The high throughout and in situ detection can be achieved by this method with further improving of the experimental system.展开更多
Using our custom-built high-pressure cryostat we have performed the measurements of the R line fluorescence of ruby in the diamond anvil cell from room temperature down to 90K.The maximum pressure was 11.1 GPa.By comp...Using our custom-built high-pressure cryostat we have performed the measurements of the R line fluorescence of ruby in the diamond anvil cell from room temperature down to 90K.The maximum pressure was 11.1 GPa.By computer curve fitting,different equations have been found for functions of wavenumber versus temperature between ambient pressure and 2.7 GPa.The changes of the shape and linewidth of R lines were observed.展开更多
We apply two-photon resonant nondegenerate four-wave mixing with a resonant intermediate state for the obser- vation of Rydberg states in sodium vapour. The broadening and shift of the sodium 3S- 11D transition pertur...We apply two-photon resonant nondegenerate four-wave mixing with a resonant intermediate state for the obser- vation of Rydberg states in sodium vapour. The broadening and shift of the sodium 3S- 11D transition perturbed by argon are investigated. This technique can achieve Doppler-free resolution of narrow spectral structures of Rydberg levels if lasers with narrow bandwidths are employed.展开更多
By using transport and magnetic measurement,the upper critical field H_(c2)(T)and the irreversibility line Hirr(T)has been determined.A big separation between H_(c2)(0)and Hirr(0)has been found showing the existence o...By using transport and magnetic measurement,the upper critical field H_(c2)(T)and the irreversibility line Hirr(T)has been determined.A big separation between H_(c2)(0)and Hirr(0)has been found showing the existence of a quantum vortex liquid state induced by quantum fluctuation of vortices in the new superconductor MgB_(2).Further investigation on the magnetic relaxation shows that both the quantum tunneling and the thermally activated flux creep depends weakly on temperature.However,when the melting field Hirr is approached,a drastic rise of the relaxation rate is observed.This may indicate that the melting of the vortex matter at a finite temperature is also induced by the quantum fluctuation of vortices.展开更多
La_(0.8)Te_(0.2)MnO_3/YBa_2Cu_3O_(7-δ)(F/S)bilayers were fabricated by electrophoretic technique. The thickness of La_(0.8)Te_(0.2)MnO_3 is ~70 μm, the dimensions of YBa_2Cu_3O_(7-δ) superconductor are 5 mm×10...La_(0.8)Te_(0.2)MnO_3/YBa_2Cu_3O_(7-δ)(F/S)bilayers were fabricated by electrophoretic technique. The thickness of La_(0.8)Te_(0.2)MnO_3 is ~70 μm, the dimensions of YBa_2Cu_3O_(7-δ) superconductor are 5 mm×10 mm×0.5 mm. The image of cross-sectional profile was measured by scanning electron microscopy (SEM). Standard four-probe method was used for YBa_2Cu_3O_(7-δ) superconducting resistance measurements. Either 1 mA current is injected from S layer to F layer ((+I_(inj))) or from F layer to S layer (-I_(inj)),the normal resistance is lower than that without current injection. The critical transition temperature is higher than that without current injection.展开更多
The effects of microstructure, cell orientation and temperature on magnetic properties and the coercivity mechanism in Sm(Co,Fe,Cu,Zr)z with low Cu content are studied by using the micromagnetic finite element metho...The effects of microstructure, cell orientation and temperature on magnetic properties and the coercivity mechanism in Sm(Co,Fe,Cu,Zr)z with low Cu content are studied by using the micromagnetic finite element method in this paper. The simulations of the demagnetization behaviours indicate that the pinning effect weakens gradually with the thickness of cell boundary decreasing and strengthens gradually with the cell size decreasing. Because of the intergrain exchange coupling, the coercivity mechanism is determined by the difference in magnetocrystalline anisotropy between the cell phase and the cell boundary phase. And the coercivity mechanism is related to not only the cells alignment but also temperature. With temperature increasing, a transformation of the demagnetization mechanism occurs from the domain pinning to the uniform magnetization reversal mode and the transformation temperature is about 650 K.展开更多
基金Supported by the National Key Basic Research Programme of China under Grant No 2002CB713805, and the National Natural Science Foundation of China under Grant Nos 10374112 and 10604065.
文摘Microtubule-associated proteins (MAPs) are important proteins in cells. They can regulate the organization, dynamics and function of microtubules. We measure the binding force between microtubule and a new plant MAP, i.e. AtMAP65-1, by dual-optical tweezers. The force is obtained to be 14.6 ± 3.5 pN from the data statistics and analysis. This force measurement is helpful to understand the function and mechanism of MAPs from the mechanical point of view and lays the groundwork for future measurements of the mechanical properties of other biological macro-molecules.
基金Supported by the National Natural Science Foundation of China under Grant No.59525206the Education Ministry of China and the Higher Education Bureau,the Science and Technology Commission of Guangdong Province.
文摘Aligned carbon nanotube (CNRT) films exhibit excellent electron emission properties at very low fields. This has been attributed to the high aspect ratio of CNTs, I.e. Their emitting surface can have high local field due to geometrical enhancement. It is found that a new mechanism can be responsible for the enhancement of the local field on the emitting surface of CNTs. This results from the space charge in the vacuum gap, which is readily generated due to the high emission current density of CNTs. Details are given of both experimental and theoretical studies of this effect. The mechanism also accounts for the distinct nonlinearity in Fowler-Nordheim plots often observed with CNTs. The implication of the technical application of our findings is also included.
文摘The lanthanum strontium aluminium tantalum oxide(LSAT)crystal is grown by means of a floating or pulling method.Its optical transmittance,refractive indices in visible and near-infrared areas and its dispersion curve are reported.The transparence range of LSAT is from 0.45 to 4.2μm and its refractive index is 2.0244.
基金Supported by the National Center for R&D on Superconductivity and the Ministry of Science and Technology of China(NKBRSF-G19990646).
文摘A way to determine some important etching parameters in the step fabrication for highTc step-edge Josephson junctions is described based on an analysis of the dynamics of the etching process.The optimum thickness of the etch mask is defined with negligible recession of the mask edge during the etch.Under this condition,the equilibrium angle of the steps etched on the SrTiO_(3)(STO)substrate with an Nb mask has been calculated to be about 76°.With optimized mask thickness,its sharp sidewall and straight edge,high-quality steps on STO substrates with step height from 200-300 nm and step angle above 70°are made.Josephson junctions and dc-SQUIDs with high reproducibility and less parameter scatter are obtained on the step substrates.
基金Supported by the National Natural Science Foundation of China under Grant No.1989380.
文摘The Trapping force on Rayleigh particles in an optical tweezers system with an oil immersion objective is calculated by an electromagnetic model.The results indicate that the stability of particles trapped will be affected by spherical aberration,which is caused by refractive difference between objective oil and water solution,when the specimen manipulated is suspended in a water solution.The trapping force and depth of potential well will decrease and the minimum of laser power for ensuring the stability of particles trapped will increase with the enhancing trapping depth.
基金Supported by the Ministry of Science and Technology of China(NKBRSF-G19990646)the National Natural Science Foundation of China under Grant No.19825111。
文摘The new superconductor MgB_(2) has been prepared by two ways: high pressure and ambient pressure synthesis. Their superconducting properties were measured and compared. It is found that the sample prepared by high pressure is much denser than that prepared under ambient pressure. Accordingly the high pressure sample has a very narrow transition width and a much higher bulk critical current density.
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 Ministry of Science and Technology of China(NKBRSF-G19990646)the National Natural Science Foundation of China under Grant No.19825111.
文摘Resistive transitions of the new superconductor MgB_(2) are carried out under magnetic fields from 0 to 8 T.It is found that the irreversibility field Hirr(T)and the upper critical field Hc2(T)obtained are very close to those determined in the magnetic measurement.By using the Arrhenius activation lawρ=ρ0exp(-U/kBT),the activation barrier U has been determined by the low dissipation part of R(T)curves.It is found that U■kBT manifests a very weak thermal activation and thermal fluctuation effect.This may further indicate that the flux dynamics near Hirr(T)is induced by strong quantum fluctuation and tunneling of vortices.
基金Supported by National Natural Science Foundation of China under Grant Nos.59702011 and 59525101the 973 State Key Program of Basic Research of China(G1998061314).
文摘Structural,magnetic,and transport properties of perovskite La_(2/3)Ca_(1/_3)Mn_(1-x)Si_(x)O_(3)(x=0,0.025,0.05)have been studied.The incorporation of Si decreases the overall resistivity,but obviously increases the Curie temperature(TC),metal-insulator transition temperature(TP),and the magnetoresistance ratio MR(defined as[R(0)-R(H)]/R(0))near room temperature.Comparing with La_(2/3)Ca_(1/_3)MnO_(3)the TC,TP,and MR of the sample with x=0.05 increase by 30,45K,and 20%,respectively.Lattice effects may play a more important role than the magnetic dilution in the case of low Si substitution.
基金Supported by the National Natural Science Foundation of China under Grant Nos.50031010,59925101 and 59871059.
文摘The linear expansion of Zr_(48)Nb_(8)Cu_(14)Ni_(12)Be_(18) bulk metallic glass(BMG)with excellent glass forming ability and high thermal stability is investigated by a dilatometry method.The average expansion coefficient is α TG=1.04 × 10^(-5) K^(-1)(300-656 K)for the BMG and α TG=1.11 × 10^(-5) K^(-1)(356~890 K)for the crystallized alloy.The Mie potential as well as the equation of state of the BMG and its corresponding crystallized state are determined from the thermal expansion and ultrasonic data,and the differences among them are phenomenologically explained.
基金the National Natural Science Foundation of China under Grant Nos.19734040,and 69778014.
文摘A series of squarylium cyanine dyes with different substituents were synthesized and the third-order optical nonlinearities of their ground and excited states were investigated by backward degenerate four-wave-mixing.For the ground state,the molecular hyperpolarizabilityγg increases with the red-shift of the absorption peakλabmax,of the squaraine with different substituents,whereas for the excited-state molecular hyperpolarizabilityγe,the nonlinear enhancementγe/γg decreases,which may indicate that in the excited state the electron accepting-donating ability of different substituents changes in the reverse order compared with the order in the ground state.
基金Project supported by the National Key Basic Research and Development Programme of China (Grant No 2001CB6104), the National Center for Nanoscience and Technology, China (Grant No 2003CB7169) and the National Natural Science Foundation of China (Grant No 10474036).
文摘We fabricated a new type of two-dimensional photonic crystal slab filter. The resonant cavities were directly put into the waveguide arms. The optical transmissions of the filters were measured and the results show that the optimized two-channel filters give good intensity distribution at the output ports of the waveguide. A minimum wavelength spacing of 5 nm of the filter outputs is realized by accurately controlling the size of the resonant cavities.
基金Supported by the National Natural Science Foundation of China under Grant No 50702077.
文摘Colloidal photonic crystal heterostructures, composed of two opaline photonic crystal films of silica spheres with different diameters, are fabricated by a two-step spin-coating method. Scanning electron microscopy (SEM) and UV-vis spectrophotometer are used to characterize the heterostructures. The SEM images show good ordering of the two-layer colloidal crystals constituting the heterostructures. The transmission spectra measured from the (111) plane in the heterostructure show that the composite colloidal photonic crystals have double photonic stop bands. Furthermore, when the sizes of the silica spheres used for fabricating the composite photonic crystal are slightly different, the transmission spectrum shows that the composite photonic crystals have more extended bandgap than that of the individual photonic crystals due to partial overlapping of its two photonic stop bands.
基金Supported by the National Natural Science Foundation of China under Grant Nos G50225209 and G50271023, the Key Foundation of Education Ministry of China under Grant G02017 and the Natural Science Foundation of Hebei Province under Grant No G503031.
文摘Infrared absorption spectra of La0.67-xPrxCa0.33MnO3 (x= 0, 0.18 and 0.36) are experimentally studied in the temperature range 20 -300K. Absorption peak splitting corresponding to the stretching oscillation of the Mn-O bond, together with a shift of peak position, is observed below the Curie temperature. These features weaken and even disappear as the samples are warmed up to the Curie temperature, which indicates that this anomaly may be a result of phase separation in the compounds.
基金Project supported by the Chinese Academy of Sciences for Key Topics in Innovation Engineering (Grant No L3FX051W)
文摘This paper reports that the detection to the protein in microarray format is carried out by oblique-incidence reflectivity difference (OI-RD) analysis without any labelling agents. The OI-RD intensities not only depend on the protein structure, but also vary with the protein concentration. The results indicate that this method should have potential application in detection of biochemical processes. The high throughout and in situ detection can be achieved by this method with further improving of the experimental system.
文摘Using our custom-built high-pressure cryostat we have performed the measurements of the R line fluorescence of ruby in the diamond anvil cell from room temperature down to 90K.The maximum pressure was 11.1 GPa.By computer curve fitting,different equations have been found for functions of wavenumber versus temperature between ambient pressure and 2.7 GPa.The changes of the shape and linewidth of R lines were observed.
基金Supported by the National Natural Science Foundation of China under Grant No.19874080。
文摘We apply two-photon resonant nondegenerate four-wave mixing with a resonant intermediate state for the obser- vation of Rydberg states in sodium vapour. The broadening and shift of the sodium 3S- 11D transition perturbed by argon are investigated. This technique can achieve Doppler-free resolution of narrow spectral structures of Rydberg levels if lasers with narrow bandwidths are employed.
基金Supported by the National Natural Science Foundation of China under Grant No.19825111the Ministry of Science and Technology of China(NKBRSF-G1999064602).
文摘By using transport and magnetic measurement,the upper critical field H_(c2)(T)and the irreversibility line Hirr(T)has been determined.A big separation between H_(c2)(0)and Hirr(0)has been found showing the existence of a quantum vortex liquid state induced by quantum fluctuation of vortices in the new superconductor MgB_(2).Further investigation on the magnetic relaxation shows that both the quantum tunneling and the thermally activated flux creep depends weakly on temperature.However,when the melting field Hirr is approached,a drastic rise of the relaxation rate is observed.This may indicate that the melting of the vortex matter at a finite temperature is also induced by the quantum fluctuation of vortices.
文摘La_(0.8)Te_(0.2)MnO_3/YBa_2Cu_3O_(7-δ)(F/S)bilayers were fabricated by electrophoretic technique. The thickness of La_(0.8)Te_(0.2)MnO_3 is ~70 μm, the dimensions of YBa_2Cu_3O_(7-δ) superconductor are 5 mm×10 mm×0.5 mm. The image of cross-sectional profile was measured by scanning electron microscopy (SEM). Standard four-probe method was used for YBa_2Cu_3O_(7-δ) superconducting resistance measurements. Either 1 mA current is injected from S layer to F layer ((+I_(inj))) or from F layer to S layer (-I_(inj)),the normal resistance is lower than that without current injection. The critical transition temperature is higher than that without current injection.
基金Project supported by the Natural Science Foundation of Zhejiang Province,China (Grant No Y407174)
文摘The effects of microstructure, cell orientation and temperature on magnetic properties and the coercivity mechanism in Sm(Co,Fe,Cu,Zr)z with low Cu content are studied by using the micromagnetic finite element method in this paper. The simulations of the demagnetization behaviours indicate that the pinning effect weakens gradually with the thickness of cell boundary decreasing and strengthens gradually with the cell size decreasing. Because of the intergrain exchange coupling, the coercivity mechanism is determined by the difference in magnetocrystalline anisotropy between the cell phase and the cell boundary phase. And the coercivity mechanism is related to not only the cells alignment but also temperature. With temperature increasing, a transformation of the demagnetization mechanism occurs from the domain pinning to the uniform magnetization reversal mode and the transformation temperature is about 650 K.