Search

An innovative heterojunction is fabricated between two sides of a freestanding thin film of HCl-doped polyaniline (PANI) derivative containing azobenzene side-chain, which is synthesized through an N-alkyl-substituted reaction. Of the film, the side with being irradiated by UV light during preparation is represented as 'A side'; the other side without being irradiated is represented as 'N side'. The electrical properties of the heterojunction are measured and the rectifying effect is observed in the current-voltage characteristic curves with the values of rectifying ratio (γ) being 20 at ±0.06 V at T = 77K and 4 at ±0.02 V at T = 300 K separately.

The anisotropy of two successive transitions of the spin-ladder compound LiCu2O2 is studied by the specific heat (C) under magnetic fields with H// c and H// ab (written as Hc and Hab in the following) up to 14 T. The peak of specific heat at 24.5 K in zero field shifts to lower temperature when the field is increased and the magnitude of the peak is suppressed by the field. On the contrary, the peak of 22.5 K shifts to higher temperature, especially at 14 T. Its magnitude increases in the field of Hc, whereas it decreases in the field of Hab. We calculate the entropy change between 21 K and 63 K. The different influence of the spin ordering by fields of different direction is obtained. Our experimental results suggest a mixed state between the long range incommensurate helimagnetic ground state and the higher-T short-range dimer liquid state. The temperature range of mixed state is shrunk with the increasing field. Possible mechanism is discussed.

We report the current–voltage (I–V) characteristics and electrical conductivity of individual template-synthesized poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires (190 ± 6 nm in diameter and ort = 11.2 ± 2 Ω−1cm-1) over a wide temperature range from 300 to 10K. With lowering temperature, the I – V characteristics become nonlinear around 50K, and a clear Coulomb gap-like structure appears in the differential conductance (dl/dV) spectra. The temperature dependence of the resistance below 70K follows inR ∞ T-1/2, which can be interpreted as Efros–Shklovskii hopping conduction in the presence of a Coulomb gap. In addition, the influences of measurement methods such as the applied bias voltage magnitude, the two-probe and four-probe techniques used in the resistance measurements are also reported and discussed.

This paper reports that the Schottky junctions between low work function metals (e.g. Al and In) and doped semiconducting polymer pellets (e.g. polyaniline (PANI) microsphere pellet and polypyrrole (PPy) nanotube pellet) have been prepared and studied. Since Ag is a high work function metal which can make an ohmic contact with polymer, silver paste was used to fabricate the electrodes. The Al/PANI/Ag heterojunction shows an obvious rectifying effect as shown in I - V characteristic curves (rectifying ratio gamma = 5 at +/-6 V bias at room temperature). As compared to the Al/PANI/Ag, the heterojunction between In and PANI (In/PANI/Ag) exhibits a lower rectifying ratio gamma = 1.6 at +/-2 V bias at room temperature. In addition, rectifying effect was also observed in the heterojunctions Al/PPy/Ag (gamma = 3.2 at +/-1.6 V bias) and In/PPy/Ag (gamma = 1.2 at +/-3.0 V bias). The results were discussed in terms of thermoionic emission theory.

Low-temperature specific heat in a dichalcogenide superconductor 2H-NbSe2 is measured in various magnetic fields. It is found that the specific heat can be described very well by a simple model concerning two components corresponding to vortex normal core and ambient superconducting region, separately. For calculating the specific heat outside the vortex core region, we use the Bardeen-Cooper-Schrieffer (BCS) formalism under the assumption of a narrow distribution of the superconducting gaps. The field-dependent vortex core size in the mixed state of 2H-NbSe2, determined by using this model, can explain the nonlinear field dependence of specific heat coefficient gamma(H), which is in good agreement with the previous experimental results and more formal calculations. With the high-temperature specific heat data, we can find that, in the multi-band superconductor 2H-NbSe2, the recovered density of states (or Fermi surface) below T-c under a magnetic field seems not to be gapped again by the charge density wave (CDW) gap, which suggests that the superconducting gap and the CDW gap may open on different Fermi surface sheets.

This paper studies the electronic transport in an individual helically twisted CdS nanowire rope, on which platinum microleads are attached by focused-ion beam deposition. The current–voltage (I –V) characteristics are nonlinear from 300 down to 60 K. Some step-like structures in the I – V curves and oscillation peaks in the differential conductance (dI/dV - V) curves have been observed even at room temperature. It proposes that the observed behaviour can be attributed to Coulomb-blockade transport in the one-dimensional CdS nanowires with diameters of 6–10 nm.

The specific heat and resistance of CeCu6-xMx (M=Ni,Zn) have been studied in the concentration range where they still retain the orthorhombic structure. The coefficient c of -ln T term in resistance R = R-0+bT-clnT, as well as the gamma, have been found to vary in opposite directions with increasing x for Ni and Zn substitutions. The physical mechanism is discussed.

Conducting microtubes (0.4–0.5μm in outer diameter) made of polypyrrole (PPy) doped with p-toluene sulfonic acid (PTSA) were synthesized by a self-assembly method. We report the electrical conductivity of an individual PPy microtube, on which a pair of platinum micro-leads was fabricated by focused ion beam deposition. The measured room-temperature conductivity of the individual PPy microtube was 0.29S/cm, which is comparable to that of template-synthesized PPy micro/nanotubes. The temperature dependence of conductivity of the individual microtube follows the three-dimensional variable-range hopping (3D VRH) model.

Results of charge-transport and magnetic measurements of nanotubular polyaniline (PANI) composites containing Fe3O4 nanoparticles (~10nm) synthesized by a ``template-free'' method are reported. The T-1/2 resistivity has been observed and dc magnetic susceptibility data are fitted to an equation χ = χ*P + C/T. With increasing weight ratio of Fe3O4, the electrical conductivity and temperature-independent susceptibility χ*P increase and the Curie-type susceptibility is suppressed at low temperatures. Further discussions have been given. The PANI-H3PO4/Fe3O4 composite containing 27wt% of Fe3O4 nanoparticles is superparamagnetic, exhibiting very little hysteresis even at 5K.

The electronic structure of T*-type compounds (Bi0.5Sr1.5)(Y2-xCex)Cu2 Oy has been studied by x-ray photoelectron spectroscopy. From analysis of the results, it was found that cation deficiency in Ce4+ introduced holes to conduction planes in the T* phase as in the p-type infinite layer compounds. Some Cu ions in the sample without cation-deficiency contained two-oxygen coordination, which resulted in the incompleteness of the CuO2 sheets. Bi ions in the T* phase cuprates take exact valence of 3+, Pb ions cannot replace them due to the too large an ionic radius of Pb2+/Pb4+.

Thermal effects on the microstructure of Bi2Sr2CaCu2Oy and (Bi, Pb)2Sr2Ca2Cu3Oy superconductors are studied by electron diffraction and differential thermal analysis (DTA). The DTA results show that there exist two endothermal peaks and one exothermal peak at about 530, 680 and 740 degrees C respectively. The electron diffraction indicates that a 2a, 2b, c superstructure is formed at about 450 degrees C. The superstructure begins to disappear at about 680 degrees C and the collapse of the crystal structure occurs at about 700 degrees C, which is consistent with the results of DTA. The superstructure originates in oxygen-vacancy ordering as for similar superstructures occurring in Bi2Sr2YCu2Oy and YBa2Cu3O7-x.

The specific heat of the recently discovered superconductor MgB2 has been measured at temperatures ranging from 4.5 to 80 K. The superconducting anomaly ΔC at Tc is clearly observed. The total specific heat in the normal state can be well fitted by electronic and phonon contributions. The Debye temperature θD is found to be 737 K, much larger than other intermetallic superconductors. The normal-state electronic specific heat coefficient γ is found to be 2.48±0.5 mJ/molK2 and ΔC/γTc is between 1.41 and 2.15.

The critical current density Jc and the n-value have been studied from 40 K to critical temperature for four types of Bi-system 2223 tapes with different sheaths. The experimental results demonstrate that the change of Jc can be divided into three parts and the n-value has some decrease with a decrease in temperature. In engineering applications, a proper working temperature can be selected to satisfy the practical requirement. Furthermore, the temperature effects on critical stress for Ag-sheath tape was also studied. The results demonstrate that the critical stress does not change monotonically with a decrease in temperature. It increases first, then decreases with the further decrease in temperature.

We have measured the resistance of some Bi2Sr2CaCu2O8 superconducting single crystals along ab plane and the c axis. For some of the single crystals, a resistivity anomaly near the superconducting transition temperature is observed in the ab plane. This giant resistance peak is independent of the small driving current (I less than or equal to 40 mA), and the peak is suppressed and vanished gradually with the increasing applied magnetic field (> 100 G). We proposed that the resistance peak is a quasi-reentrant behavior due to the superconducting phase inhomogeneous distribution.

The current-voltage characteristics in different magnetic fields are measured on a whisker (2 mm x 0.037 mm x 0.007 mm) of highly anisotropic material Bi2212 with field H parallel to c-axis and H parallel to b-axis, respectively. When H parallel to c-axis, the j(c) versus T relation remains normal for all fields. However, when the field H is along the b-axis, we obtained an abnormal j(c) versus T relation with a peak value appearing at T = 25 K in H = 4 T. The possible explanations are discussed. (C) 2000 Elsevier Science B.V. Ail rights reserved.

We found a normal-state reentrant behavior in zero field near the critical temperature of a Bi2212 crystal when we applied current along c-axis direction and measured the ab plane voltage. A similar phenomenon is observed in a Zn substituted Bi2212 crystal. The new phenomenon may be due to destroying of the Cooper pairs in the ab plane by the injected normal electrons.

The moisture and ethanol dependences of electrical properties of polyaniline (PANI) nanotubes doped with naphthalene sulfonic acid (NSA) are reported. The experiments were carried out in a temperature range from 80 to 300K. On the basis of analyzing the characteristics of the samples, we suggest that the resistance of the samples is dominated by the contact resistance between the PANI nanotubes, and the observed lnR(T)∝T-1/2 relation is explained in terms of the charge-energy-limited tunneling (CELT) model. The presence of water or ethanol molecules increases the conductivity, which is ascribed to the enhancement of charge carrier transfer and contact interface between the nanotubes upon exposure to water and ethanol. However, the extent of change during exposure to water and ethanol can be attributed to the differences in their chemical structures as well as their physicochemical properties.

We report the low-temperature resistance under a magnetic field (μ０0H=0, 5 and 10T) within the temperature range from 18 to 300K and low temp erature (T=19 and 15K) magneto_resistance (μ00H=0—10T) of hea vy electron compounds CeCu6-x6-xCdxx(x=010，015 ，020，0 30，050). The experiments show that the Tmaxmax（correspondin g to the max imal resistance）of all samples are not observed over 18K under zero magneti c field. When a magnetic field is applied, the Tmaxmax increases with inc reasing magnetic field and doping content x. Meanwhile, the magneto_resista nces are all negative at 19K and the positive magneto_resistance of part of samples is observed at 15K. This phenomenon can be explained by Kondo scatteri ng and coherent scattering.

In this paper, we report the resistance, specific heat and susceptibility of heavy electron compounds CeCu5.8M0.2(M=Ni，Zn，Cd) as functions of temperature from 1.8 K to 300 K. The effects of magnetism, valence and atom size of different doping elements on Kondo temperature TK, coherent temperature TRmax (e.g. the temperature of maximum resistance) and other parameters have been discussed.

The temperature dependence of magnetic properties for Nd60Al10 Fe20Co10 bulk metallic glass is investigated. The re sults indicate that th e Nd60Al10Fe20Co10 bulk metallic gla ss exhibits permanen t magnetic behaviour at room temperature. The coercive force and the shape of hy steresis loops change markedly when temperature decreases. AC magnetic susceptib ility is measured and a peak at about 18K is found. The peak moves torwards high temperatures when the frequency is increased. This indicates that there are spi n glass structures in the bulk metallic glass.

The specific heat of the emeraldine base form of polyaniline and the emeradine salt of polyaniline has been measured at temperatures between 1.8 and 45K. The experimental results have been interpreted in terms of the contributions from both the crystalline and the amorphous phases characterizing the polymer. Anomaly of the specific heat, which is much larger than that expected from the Debye theory, has been successfully explained by the phonon-fracton model at low temperatures. The electronic specific heat has not been observed from the present data.

We report on the specific heat of a Bi 2 Sr 2 CuO y single crystal measured between 0.1K and 5K. The measurements were carried out with the single crystal first in the semiconducting state and then, after oxygenation in a superconducting state. The specific heat of the latter showed a well defined peak centred at 4.1K associated with the superconducting transition. At low temperatures both states exhibited a 1/T 2 term associated with the nuclear spins of the copper ions. In addition both could be fitted well to a function which includes a residual term of the form αT n where n is less than unity. The exponent n is smaller for the superconducting state than for the semiconducting state, as is found in some other systems.

报道了两类典型元素替代的超导Y123相体系－YBa2(Cu1-xCox)3O7-δ（x=0.01,0.02)和YBa2(Cu1-yZny)3O7-δ（y=0.005,0.010）薄膜的电阻率－温度特性（ρ（T））和Hall效应（RH（T））。研究表明，Co掺杂的Y123相体系十分类似于氧欠掺杂的情况，对Co掺杂的薄膜样品，由电阻率－温度特性定义的赝能隙打开的温度T＊分别为193和225K。而n掺杂的样品没有观察到赝能隙打开对电阻率－温度特性的影响。由Hall效应的测量和Hall角（cotθH）定义了另一个特征温度T^0,介于Tc与T＊之间，这一特征温度与核磁共振（NMR）给出了赝能隙打开温度相近，说明可能源于电子自旋自由度上的能隙打开。在室温到Tc范围内，电阻率－温度特性和Hall效应分别定义了两类不同的转变温度（T＊和T^0），可能分别源于电子电荷和自旋通道上的赝能隙的打开，预示着电荷和自旋自由度分别进入某种基态。

Ｉｎｔｈｉｓｐａｐｅｒ,ｔｈｅｅｘｐｅｒｉｍｅｎｔａｌｒｅｓｕｌｔｓｏｆｔｈｅｌｏｗ ｔｅｍｐｅｒａｔｕｒｅｒｅｓｉｓｔａｎｃｅｂｅｔｗｅｅｎ 0.1Ｋｔｏ 2 50Ｋａｎｄｓｐｅｃｉｆｉｃｈｅａｔｂｅｔｗｅｅｎ5Ｋｔｏ 70ＫｏｆｈｅａｖｙｆｅｒｍｉｏｎｃｏｍｐｏｕｎｄｓＣｅＣｕ6 ｘＮｉｘ(ｘ =0.0 ,0.0 5,0.1 ,0.15,0.2 )ａｒｅｒｅｐｏｒｔｅｄ .ＴｈｅｄｏｐｉｎｇｅｆｆｅｃｔｏｆｔｈｅＮｉｃｏｎｔｅｎｔｏｎｔｈｅｌｏｗ ｔｅｍｐｅｒａｔｕｒｅｐｒｏｐｅｒｔｉｅｓｏｆＣｅＣｕ6 ｉｓｓｔｕｄｉｅｄ .Ｔｈｅｔｅｍｐｅｒａｔｕｒｅｓｏｆｒｅｓｉｓｔａｎｃｅｍａｘｉｍｕａｓｏｆｔｈｅｓａｍｐｌｅｓｒｅｄｕｃｅｄｒａｍａｔｉｃａｌｌｙｗｉｔｈｔｈｅｉｎｃｒｅａｓｅｏｆｔｈｅｄｏｐｉｎｇｃｏｎｔｅｎｔｘ.ＴｈｉｓｉｎｄｉｃａｔｅｓｔｈｅｅｎｈａｎｃｅｍｅｎｔｏｆｍａｇｎｅｔｉｃｍｏｍｅｎｔｏｆｍｉｎｏｒＣｅｉｏｎｓｔｈａｔａｒｅｎｅｉｇｈｂｏｒｉｎｇＮｉａｔｏｍａｎｄｔｈｅｄｅｃｒｅａｓｅｏｆｔｈｅｃｏｈｅｒｅｎｔｓｃａｔｔｅｒｉｎｇｂｅｔｗｅｅｎｔｈｅｗｈｏｌｅＣｅｉｏｎｌａｔｔｉｃｅａｎｄｔｈｅｃｏｎｄｕｃｔｉｏｎｅｌｅｃｔｒｏｎｓ.Ｔｈｅｌｏｗ ｔｅｍｐｅｒａｔｕｒｅｅｌｅｃｔｒｏｎｉｃｓｐｅｃｉｆｉｃｈｅａｔｃｏｅｆｆｉｃｉｅｎｔγ(ＣＥ Ｔ ,ｗｈｅｒｅＣＥｉｓｔｈｅｅｌｅｃｔｒｏｎｉｃｓｐｅｃｉｆｉｃｈｅａｔ)ｉｓｎｅａｒｌｙａｃｏｎｓｔａｎｔａｔｌｏｗｔｅｍｐｅｒａｔｕｒｅｓ,ｂｕｔｉｔａｐｐａｒｅｎｔｌｙｉｎｃｒｅａｓｅｓｂｅｌｏｗ 8Ｋｄｕｅｔｏｔｈｅｉｎｃｒｅａｓｅｏｆｉｔｓｅｆｆｅｃｔｉｖｅｍａｓｓ.Ｈｏｗｅｖｅｒ,ｔｈｅｔｅｍ ｐｅｒａｔｕｒｅａｔｗｈｉｃｈγｂｅｇｉｎｓｔｏｉｎｃｒｅａｓｅｉｓｎｏｔｓｅｎｓｉｔｉｖｅｔｏｔｈｅｃｏｎｔｅｎｔｏｆＮｉ,ｉｎｄｉｃａｔｉｎｇｔｈａｔｔｈｅｓｔａｔｕｓｏｆｍｏｓｔｃｅｒｉｕｍｉｏｎｓａｒｅｎｏｔａｆｆｅｃｔｅｄ.

Ｗｅｒｅｐｏｒｔｔｈｅｐａｒｔｉｃｕｌａｒｓａｍｐｌｅｐｒｅｐａｒａｔｉｏｎｍｅｔｈｏｄａｎｄｔｈｅｅｘｐｅｒｉｍｅｎｔａｌｒｅｓｕｌｔｓｏｆｔｈｅｌｏｗ ｔｅｍｐｅｒａｔｕｒｅｒｅｓｉｓｔａｎｃｅａｎｄｓｐｅ ｃｉｆｉｃｈｅａｔｏｆｈｅａｖｙｅｌｅｃｔｒｏｎｍｅｔａｌｓＣｅＣｕ6 -ｘＺｎｘ(ｘ=0 .0 5,0 .1 0 ,0 .1 5,0 .2 0 ,0 . 3 0 ) .ＴｈｅｐｈｙｓｉｃａｌｏｒｉｇｉｎｆｏｒｔｈｅｅｆｆｅｃｔｏｆｔｈｅＺｎｃｏｎｔｅｎｔｏｎｔｈｅｌｏｗ ｔｅｍｐｅｒａｔｕｒｅｐｒｏｐｅｒｔｉｅｓｏｆＣｅＣｕ6 -ｘＺｎｘａｒｅｓｔｕｄｉｅｄ.ＷｅｆｉｎｄｔｈａｔｂｏｔｈｔｈｅｃｏｅｆｆｉｃｉｅｎｔｃｏｆＫｏｎｄｏｓｃａｔｔｅｒｉｎｇｔｅｒｍａｎｄｔｈｅＴｍａｘｃｏｒｒｅｓｐｏｎｄｉｎｇｔｏｔｈｅｍａｘｉｍａｌｒｅｓｉｓｔａｎｃｅｄｅｃｒｅａｓｅｓｗｉｔｈｉｎｃｒｅａｓｉｎｇＺｎｃｏｎｔｅｎｔ.ＷｈｉｌｅｔｈｅＤｅｂｙｅｔｅｍｐｅｒａｔｕｒｅｏｆＣｅＣｕ6 -ｘＺｎｘｓｌｉｇｈｔｌｙｇｏｕｐｗｉｔｈｉｎｃｒｅａｓｉｎｇＺｎｃｏｎｔｅｎt.

Magnetic hysteresis loops were measured on Bi2Sr2CaCu2O8 single crystals with a vibrating sample magnetometer. An anomalous second magnetization peak was observed between 20 and 40K. The magnetic fields showing peak effect in over-doped crystal were observed to be higher than the optimally doped samples. The disorder-driven transition shifted to lower fields with increasing point disorder. At lower temperatures the quasilattice transformed into a disordered solid as the field was increased above the second magnetization peak. There was not any transition from the ordered solid quasilattice to a disordered solid below 20K in schematic vortex matter phase diagram in BSCCO. The peak effect was a complicated function of magnetic field, temperature and material disorder.

Specific heat of the bulk amorphous Zr-Ti-Cu-Ni-Be alloy and different heat-treated samples has been measured in temperature range from 4.5 to 30K. The specific heat result can be well fitted by electronic and phonon contributions. The value of electronic specific coefficient γ is much bigger than other samples and the Debye temperature ΘD increases regularly from amorphous to equilibrium crystallized phase. The different behaviors of different samples are interpreted primarily in terms of electronic density of states and Debye model.

We have measured the resistance of some Bi2Sr2CaCu2O8 superconducting single crystals along ab plane and the c axis. In some single crystals, a remarkable resistivity anomaly near the superconduct ing transition temperature is observed in the ab plane. The peak is suppressed a nd vanishes gradually with increasing applied magnetic field (>100Gs) or transpo rt current. We proposed that the resistance peak is a quasi-reentrant behavior d ue to the inhomogeneous distribution of the superconducting phase.

CeNiSn is an interesting heavy fermion compound,with its ground state being a Kondo insulator.The effect of the substitution of Ni by Cu on the specific heat of CeNi1-xCuxSn polycrystal samples is studied through the m ethod of chemical element substitution.A series of samples (x=00,0.02,0.06,0.0 6) were prepared with an electric arc furnace in the atmosphere of flowing high purity argon gas.X-ray powder diffraction analysis shows that all the final samp les have single-phase structure,and that,with the increase of the substitution a mount of Ni,the crystal parameters of the samples become larger.The specific hea t measurements were performed with an adiabatic colorimeter.The results indicate that the doping of Cu increases the specific heat at low temperature,and that t he V-shape gap is gradually suppressed.The physical mechanism may be that the do ping of copper brings about the Kondo lattice discorder and the increase in 3d e lectrons.

We present simultaneous measurements of the low temperature (0.04K to 1.2K) specific heat and thermal conductivity for a series of four sintered samples from the La 2−x Sr x CuO 4 system. By systematically varying the strontium (hole) concentration from x =0.05 (near-insulator) through to x =0.27 (near-metallic), we were able to study the thermal properties of the different superconducting regimes in this cuprate system. The thermal conductivity data are characterised by a weakening of the temperature dependence from T =3 to T =1 , observed in all the samples below 1K. A linear temperature variation in the specific heat data for the two most inhomogeneous superconductors ( x =0.05 and 0.27) was replaced by a T 0.5 dependence for the samples with the higher transition temperatures ( x =0.1 and 0.15). The specific heats of all the samples showed a large upturn (proportional to T −2 ) at the lowest temperatures. The coefficients of this T −2 term were found to have a minimum for x =0.15. We discuss these effects in terms of possible transport mechanisms.

The thermal conductivity and the electrical conductivity of Cr75FexMn25-x(x=16,18) alloys have been measured over the temperatures range from 77K to 300K. The change of slope on thermal conductivity-temperature curve and the maximum on electrical conductivity-temperature curve have been found near the transition temperature of spin density wave type antiferromagnetism, which is related to the opening of the energy gap. Both alloys exhibit a rise in the phonon thermal eonductivity with decreasing temperature as being characteristic of umklapp processes.

No-resonant microwave absorption signals in BiPI SbSrCaCuO samples with different si zes and in coarse vacuum were measured, the experiment showed that the signals related to the grain size of the sample and oxygen atmosphere. The signal intensity was proportional to the Meissner state volume which was a shell layer of the skin effeet in the penetration layer.

The sample with the nominal composition Bi2Sr2Ca1-xBaxCu2Oy(A),Bi1.7Pb0.3Sr2Ca2-xBaxCu3Oy(B) were synthesized by solid state reaction. The analyses of phases and structure of the samples showed that a new kind of monoclinic phase exists in Bi-system with cell dimension a=24.84?, b=6.29?, c = 20.70?, β=114.2?. There exists special relation between the monoclinic phase and the superconducting property of Bi system. For 2212 phase, the diamagnetic transition at 95K was observed when the monolinic phase co-existed with 2212 phase, furthermore the addition of Ba ions facilitated the formation of the monoclinic phase. For Ba-doped 2223 phase, the study of electron diffraction indicated that Ba ions got into the 2223 phase and caused the change of crysral micro-structure of 2223 phase, a new additional superstructure appeared along b axis, and two kinds of modulation mode were observed simultaneously along this direction, the wavelength of which is 27?, 43? respectively. The measurement of physical property showed that the zero resistance temperature of the samples can reach as high as 113-114K by proper doping of Ba ions, and the diamagnetic transtion at 118K was also observed. This kind of increasing of the critical temperature of 2223 phase may be related to changes of its crystal microstructure.

Magnetization curves for the Bi2-xPbxSr2Ca2Cu3Oy system at different temperatures are reported. There are two phases with different critical temperatures. Corresponding to the two phases, two lower critical fields Hc1(0) are obtained.

The temperature of zero resistance of the previously reported 120K superconductor in the BiSbSrCaCuO system was 75 K. We added Pb to the BiSbSrCaCuO system, so that the temperature of zero resistance was raised to 108 K.