Vol. 35, No. 5 (1986)
1986-03-05
CONTENT
1986, 35 (5): 561-569.
doi:10.7498/aps.35.561
Abstract +
The real relation between average voltage across a two junctions SQUID and applied magnetic field have been derived. The calculations have been carried out on the variations of the instantaneous voltage with time in a given magnetic field. It is also shown theoretically that the V(t) relation is not periodical, and the V(t) amplitude is not constant.Finally, a physical interpretation about the instantaneous voltage process is given.
1986, 35 (5): 570-576.
doi:10.7498/aps.35.570
Abstract +
This paper presents a synthetical experimental research about the mechanisms of high-field Jc and alloying additives on Nh3Sn diffusion films.
1986, 35 (5): 577-582.
doi:10.7498/aps.35.577
Abstract +
In this paper, we report the synthesis of a new metastable superconducting phase formed during the process of the crystallization of amorphous La72Si28 alloy. As starting material, the La72Si28 amorphous ribbons were prepared from melt by rapid quenching method. The new metastable phase appeared when the amorphous sample was treated at 250℃ for 30 minutes. This phase has a ortborhombic structure with lattice parameters α=9.12l?, b=6.821? and c=3.833?, and exhibits superconducting transition at Tc =3.02 K which is higher than those of all the known La-Si phases.
1986, 35 (5): 583-589.
doi:10.7498/aps.35.583
Abstract +
Temperature dependence of the electrical resistivity of Fe100-xBx,Fe87-xSixB13,(Fe1-xCox)78Si9.5B12.5,(Fe1-xMx)80-84B16-20(M = Zr, V, Nb, Ta, Cr, Mo, W, Mn) amorphous alloys in the range of 4.2-300 K has been studied in this work. The experimental results demonstrated that the resistivity minima phenomena appear in all these samples. The temperature of resistivity minim Tmin increases with increaing Si or B content in the amorphous FeB and FeSiB alloys. It has been shown that as transition metal elements on the right of Fe in the periodic table are added to the Febased amorphous alloys, lower Tmin are observed, and on the other hand, as transition elements on the left of Fe are added, Tmin are shift to higher temperatures. The dependence of the added elements on Tmin of the Febased amorphous alloys shows clear regularities. Below temperature Tmin, their resistivty can be described by alogarithmic temperature dependence and a discussion of this phenomenon is given in terms of the Kondo-like scattering. Above Tmin, a T2 temperature dependence of resistivity can be explained by extended Zi-man theory for FeB, FeSiB and FeCoSiB amorphous alloys and may be originated from both, electron-phonon and localized spin-fluctuation scattering for the Fe-based amorphous alloys with addition of transition elements on the left of Fe.
1986, 35 (5): 590-597.
doi:10.7498/aps.35.590
Abstract +
The cause of some accidental degeneracy in the molecular vibrations is discussed. We pointout that the accidental degeneracy would become a natural one under an extended " exchangepoint group". A method for treating such non-unitary symmetry is also suggested.
1986, 35 (5): 598-604.
doi:10.7498/aps.35.598
Abstract +
On the basis of the correlated wave function theory, we have solved the real space integral equation for the pair correlation function, and obtained the pair correlation function, correlation energy and many-body wave function for the metals Al (rs=2.07) and Cs (rs=5.65). This work improves on the imperfections of other many-body theories. The pair correlation functions obtained in this paper are positive definite and satisfy the normalization condition.
1986, 35 (5): 605-614.
doi:10.7498/aps.35.605
Abstract +
A DPT ferroelectric ceramics system of (Ba1-xLax)(Ti1-yZry)O3 and a DPT-SPT ferroelectric crystal serise of K0.2Na0.2(SrpBa1-p)0.8Nb2O6 have beenprepared by the ordinary ceramics manufacture technique and Czochralski technique respectively. The curves of dielectric constant vs. temperature of all samples have been measured. The semi-quantitive point-analyses of composition distribution have been obtained by the technique of SBM and EDAX. The inhomogeneity of composition distribution was discovered in both DPT ceramicses and DPT single crystal, but in SPT crystal no such fluctuation was found. It was shown that the diffuse curves of ε(T) is related to composition fluctuation directly. Therefore the Smolensky's composition fluctuation model for DPT was proved in experiment. According to this model, there is a statistical distribution of transition temperature, inside the DPT ferroelectrics. The theoretical calculation of dielectric constant with the change of temperature of all samples were done by using two different expressions of ε′(T, Tc). The theoretical results agree well with experimental curves.
1986, 35 (5): 615-622.
doi:10.7498/aps.35.615
Abstract +
The scalar field theory at finite temperature of real time suggested by Nieme and Semenoff is extended to the ease of gauge field. It is useful in finite temperature QCD in Minkowski space. With the propagator of finite temperature QCD introduced in this paper, the two-loop correction of free energy of high temperature QCD is calculated and the result is consistent with that obtained by Kapusta with the method of Euclidean field theory.
1986, 35 (5): 623-632.
doi:10.7498/aps.35.623
Abstract +
Based on microstrueture image of typical nonliear ZnO ceramics (ZnO varistors), an intuitive and simple physical model of conduction has been proposed, that can quantitatively discribe the characteristics of ZaO varistors. According to this mode], in low bias voltage, electrons pass through SIS heterojunction and SS homojuction (in parallel) mainly by thernionic emission. Above breakdown voltage, SS homojuction is active juction of conduction. In this case, the reverse-biased barrier layer is transformed from depletion layer to strong inversion layer. The thickness of barrier top becomes thinner, and tunnelling electron flux rises sharply. Hence the nonliear conduction is produced. In high bias voltage, conduction is limited by grain resistivity.
1986, 35 (5): 633-637.
doi:10.7498/aps.35.633
Abstract +
The model of conduction proposed in the previous paper is treated quantitatively. This model is suitable for the explanation of V-I curve, C-V(DG) curve, and degradation phenomena of ZnO varistors. In addition, this model can also predict the influence of the microstrueture parameter and the elec trical characteristics parameter of grain-grain contact on the electrical characteristics of ZnO varistors. It provides a basis of the theory for materials design of ZnO varistors.
1986, 35 (5): 638-642.
doi:10.7498/aps.35.638
Abstract +
The experiments were done using p+u junction irradiated with 12MeV electron. Pour electron traps were observed in Si layers: A-center E1(Ec -0.19 eV), the divaeancy E2 (Ec -0.24 eV), and E4 (Ec -0.44 eV), and E3 defect level (Ec- 0.37eV). Using DLTS method in conjuntion with the reverse recovery technique, annealing behavior of E1, E4 and E3 traps have been studied. The annealing temperature of the E3 defect is the highest (≈520℃). We get an activation energy for thermal annealing of 1.71 eV with a frequency factor of ～1.5×109s-1. The E3 and E4 defect levels are the principal recombination center that controls lifetime of minorities following irradiation. As the E2 and E4 defect level annealout, however, defect level E3 becomes the dominant recombination center.
1986, 35 (5): 643-652.
doi:10.7498/aps.35.643
Abstract +
The crystal structure of the partly deuterized triglycine sulfate was studied by four-circle neutron diffractometer. The result is compared with TG-S data obtained by Kay et al. The distance between triglyeines groups increases hlightly by deuterization, The relative increases of lattice parameters a, b and c are 0.47%, 0.50%, 0.19%, respectively. The probability of deuterium substitution, P, on various hydrogen sites is obviously divided into two classes; P=0 for hydrogens locked in C-H bonds, while P= 0.84±0.03 for all the others.
BRIEF REPORT
1986, 35 (5): 653-656.
doi:10.7498/aps.35.653
Abstract +
The transmittance of a crystal can be expressed in terms of the photon's Green function (GF), solved by the equation of motion method for the GF and evaluated numerically. In the particular case of absorption of two phonons by an anharmonic crystal the formulae are derived for the, self energy of the photons and then for the transmittance of the crystal.
1986, 35 (5): 657-661.
doi:10.7498/aps.35.657
Abstract +
The magnetic properties of the spin glass La FeyNi5-y (0.5≤y≤1.1) are reported. The spin freezing temperatures, Tf, in these alloys have been measured. It is observed that at lower temperatures there is a transition from the paramagnetic (PM) to the ferromagnetic (FM) phase for y≤0.9 and the Fe-content dependence of the freezing temperature is approximately linear. There is a transition from the PM to the FM and from the FM to spin glass phase for y≥1.0.
1986, 35 (5): 662-666.
doi:10.7498/aps.35.662
Abstract +
Shift and broadening of W4f peak were observed in the course of reduction of WO3 during Ar+- and H+-bombarding in different energies. Three different doublets W+6, W+4 and W0 corresponding to W4f electrons were obtained by decomposing the spectrum. The reduction is interpreted by defect states of oxygen. The UPS spectrum shows an increase of the density of states near the Fermi energy.
1986, 35 (5): 667-671.
doi:10.7498/aps.35.667
Abstract +
The segregation kinetics and surface structures of sulfur on the Mo(111) surface have been studied by means of AES and LEED in the temperature range between 700℃ and 800℃. When the sample was heated to 800℃, sulfur segregated rapidly and progressively replaced the carbon on the surface. However, as heated to 700℃, no significant sulfur segregation has been observed. An AES analysis also showed that sulfur segregation may be controlled by its bulk diffusion rate and the presence of carbon on the surface might inhibit the surface segregation of sulfur. LEED patterns of new surfacestructures, namely Mo(111) (31/2×31/2)R30°-S and Mo(lll) l/3(99-44)-Shave beenobserved respectively.
1986, 35 (5): 672-676.
doi:10.7498/aps.35.672
Abstract +
After bombarding the Mo (111) surface with nitrogen ions of the energy of 1 keV and the beam current of 6 μA for 15 min, a very strong Auguer peak of nitrogen appeared in AES. The LEED observation showed that surface structure was disordered after annealing in the temperature range from room temperature to 450℃. The stable square pattern appeared at 562℃ can be interpreted in terms of c(3×1)-N, O overlayer structure on the Mo (433) faceting planes.
1986, 35 (5): 677-680.
doi:10.7498/aps.35.677
Abstract +
The Gd-Ni binary system has been reinvestigated by X-ray diffraction method and differential thermal analysis. The phase diagram has been determined. In this system, the following nine intermetallic compounds were found: Gd3Ni (decomposes at 735℃), Gd3Ni2 (decomposes at 690℃), GdNi (M. P. 1280℃) GdNi2 (decomposes at 1010℃), GdNi3(decomposes at 1110℃), Gd2Ni7(decomposes at 1200℃), GdNi4(decomposes at 1270℃), GdNi5(M. P. 1480℃) and Gd2Ni17(decomposes at 1285 ℃). Three eutectics occur: Gd3Ni-Gd3Ni2(635℃, ～32 at% Ni), GdNi2-GdNi2(880℃ ～56 at% Ni) and Gd2Ni17-Ni(1275℃, ～95 at Ni). Neither Go in Ni nor Ni in Gd shows any detectable solid solubility.
1986, 35 (5): 681-686.
doi:10.7498/aps.35.681
Abstract +
In this paper, the RKKY interaction formula of 2-dimensional magnetic alloy is derived by using the Green's function method. The result for large 2kfRji is in analogy to results of 1-dimensional and 3-dimensional magnetic alloy. Based on RKKY interaction formula, the RKKY Coupling resitivity of 2-dimensional magnetic alloy is calculated, it is divergent as T-1 at low temperatures. The T-1 divergencl can be removed by means of the ring approximation.
1986, 35 (5): 687-690.
doi:10.7498/aps.35.687
Abstract +
Under the BCS mechanism, we use Anderson model to explain CeCu2Si2 supereon-ductiv critical temperature change with pressure in low pressure range.
1986, 35 (5): 691-696.
doi:10.7498/aps.35.691
Abstract +
The phase diagram of pseudo-binary system LiNaS04-MgSO4 system has been studied by means of DTA and X-ray diffraction technique. Three compounds (LiNa)0.8Mg0.20.8·Mg0.2 SO4 (LiNa)0.67Mg0.33 SO4 and (LiNa)0.4 Mg0.6 SO4 have been found in this system.The ionic conductions in these three compounds have been investigated. The ionic conductivities at 490℃ are 6.1×10-5S ·cm-1, 6.5×10-5S·cm-1 and 9.8×10-6S·cm-1 with activa tion energies 1.67 eV, 1.48 eV and 1.32 eV, respectively. The prototype high temperature thermal batteries Mg/MnO2 using these compounds respectively as electrolyte have been made and tested. The results show that, Mg/ (LiNa)0.8Mg0.2 SO4/MnO2 cell has better Polarization and discharg behaviour than the others. Hence (LiNa)0.8Mg0.2SO4 might be used as electrolyte in high temperature thermal battery.