Electrical resistivity of amorphous alloys

Amorphous alloys of Ga, Sn, Pb and Bi with Cu, Ag and Au are produced by evaporation on a cold substrate. The residual resistivity, the temperature dependence of the resistivity, the transition temperature of superconductivity and the temperature of the amorphous-crystalline transformation are measured. We observe e.g. that the residual resistivity increases with the noble metal concentration, and that the temperature coefficient of the resistivity of the Au alloys is always negative. In these two respects amorphous alloys differ in behaviour from the corresponding liquid alloys. These observations can be correlated with the atomic energy levels of the free atoms.     

Electrical resistivity of heusler alloys

The electrical resistivity of eight different Heusler alloys is discussed in terms of electron phonon and spin-disorder scattering. The systematics common to the alloys can be explained in the intermediate to high temperature range while the low temperature range still presents interpretation difficulties.     

Electrical resistivity in disordered,polycrsytalline FeNiTe alloys

Many disordered, crystalline and non-crystalline alloys and metallic conductors are characterized by positive as well as negative temperature coefficients of resistivity α(T) over a wide range of temperature. Experimental results are presented here to show the anomalous behaviour of resistivity with temperature in contrast to the existing theories. The anomalous electron properties can be understood in terms of an attractive interaction between conduction electrons and the localized excitations arising from structural deformity in the atomic arrangements. This scattering mechanism is used to explain the unusual departure from a linear temperature dependence above the Curie temperature (T_c) in Fe₂₈Ni₂₈Te₄₄, Fe₂₁Ni₂₂Te₅₇, Fe₁₆Ni₂₁Te₆₃ and Fe₈Ni₁₆Te₇₆ alloy.     

Electrical resistivity and antiferromagnetism of chromium-platinum alloys

Electrical resistivity, ?, has been measured as a function of temperature, T, of Cr alloys containing 0.47, 0.93, and 1.63 at.% Pt. The onset of antiferromagnetism causes anomalies in the ? vs T curves which increase with increasing Pt concentrations. Using the criterion that at the Néel temperature, T_N, d?/dT is minimum, it has been determined that the values of T_N are (430 ± 10)K, (490 ± 5)K, and (535 ± 5)K for the above-mentioned alloys. The nature of the antiferromagnetic state and the corresponding anomalies in the electrical resistivity in the Cr-Pt system are very similar to those found in Cr-Ir solid solutions.     

Electrical resistivity of metastable Ag-Ni alloys

We have successfully prepared solid solution metal films of Ag-Ni with Ni content to 23.4 at.%. Four-probe resistivity measurements were conducted between 2.5 and 300°K and while no anomalies of the magnetic type were observed, the temperature dependence of the resistivity indicates significant deviations from Matthiessen's rule.     

Electrical resistivity of liquid gold-silicon alloys

The electrical resistivity of liquid Au_1?xSi_x alloys was measured in the gold-rich concentration range, 0.16 ? x ? 0.40, as a function of temperature and composition. In this region the temperature coefficients of the resistivity is negative. The resistivities and temperature coefficients are compared with recent data on amorphous sputtered films; for x ? 0.31 the resistivities of the films are in agreement with those of the liquids within the accuracy of the measurements. The results can be interpreted in terms of the Ziman theory.     

Electrical resistivity of amorphous Sn-Cu alloys

The residual resistivity of amorphous Sn-Cu alloys increases with the Cu-concentration. Both positive and negative temperature coefficients are observed. The positive temperature coefficient and the transition temperature of superconductivity depend linearly on the Cu-concentration and both vanish simultaneously.     

Electrical resistivity of liquid binary and ternary alloys

New method of calculation of the electrical resistivity of liquid and amorphous alloys is presented. The method is based on the Morgan–Howson–S̆aub (MHS̆) model but the pseudopotentials are replaced by the scattering matrix operators. The Fermi energy is properly determined by the accurate values of the phase shifts. The model depends on a very small number of universal parameters and gives stable results. The calculated values of the resistivity agree well with available experimental data for a substantial number of binary alloys. Moreover, the results for some ternary alloys were also obtained.     

Electrical resistivity and magneto-resistance of very dilute Cu-Cr alloys

Measurements of the electrical resistivity from 1.5–80 K and the longitudinal magnetoresistivity from 0–95 kOe at 1.9, 4.2 and 25 K for every dilute Cr in Cu alloys are reported.     

Electrical resistivity of Co-Ga alloys at high temperatures

The rotating magnetic field method was used to investigate the temperature dependences of the electrical resistivity of Co-Ga alloys in the temperature range 800–1750C. The experimental data obtained for the liquid phase are compared with the results of a calculation made in the framework of the Faber — Ziman method as generalized by Evans to alloys of transition metals.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 61–67, December, 1978.     

The effect of hydrogen on the superconducting and structural properties of b.c.c. Nb-Ru alloys

The superconducting transition temperature (T_c) has been measured before and after the introduction of hydrogen into Nb_(1?x)Ru_x$\text{(0.20?x?0.33)}$. In all cases, the presence of appreciable amounts of this interstitial component led to a sharp increase in the T_c. All the evidence suggests that conversion of the host metal lattice to f.c.c. is necessary for the appearance of the elevated T_c.     

Electrical resistivity and glassy behaviour in crystalline metallic alloys

Positional disorder due to loss of translational symmetry is suggested as being responsible for most of the concentration dependence of the electrical resistivity of certain disordered transition metal alloys. It is then argued that in such cases the existence of tunneling states should be observable at low temperatures. Measurements of the thermal conductivity on Ti_0.67V_0.33 between 0.06 and 10 K confirm this conjecture.     

Electrical resistivity study of some lead-borate glasses

We present the results of electrical resistivity measurements performed on 20Fe₂O₃80[3B₂O₃(1?x)PbOxA_uO_v] glasses, with AuOv=K₂O, Ca, As₂O₃ and GeO₂. For a given temperature the electrical conductivity is linearly dependent on the fraction of ferrous ions. The experimental data are well described by using a model involving small polarons.     

Electron-phonon interaction and coulomb pseudopotential in AuGa alloys from resistivity and superconductivity measurements

Measurements of the electrical resistivity as a function of temperature from 250 to 270 K for Au and f.c.c. phase AuGa alloys are presented. The linear dependence of the resistivity with temperature and previous results of the superconducting transition temperature of the alloys are used to obtain a value for T_c of pure Au. From these results a new method is introduced to estimate the Coulomb pseudopotential μ¹ for gold.     

Electrical resistivity of iron-vanadium alloys between 78 and 1200 K

Electrical resistivity (?) of FeV alloys containing 0.5, 0.9, 2.7, and 6.1 at% V has been measured as a function of temperature (T) between 78 and 1200 K. The ? vs. T curves exhibit a change in the slope at the ferromagnetic Currie temperature (T_c). The d?/dT vs. T curves in the neibhorhood of T_c are similar to the corresponding plot for pure Fe. Our studies confirm the previously observed anomalous effect of V on T_c of Fe, i.e., that T_c increase with small additions of V to Fe. The critical index λ⁺ associated with the power law of d?/dT just above T_c has been determined as a function of V concentration.     

Electrical resistivity of liquid CuGa alloys with Mn impurities

The electrical resistivity of liquid copper-gallium alloys with manganese impurities of two atomic percent has been determined by a DC-method. Compared to the pure alloys, the impurity atoms cause an increase of the resistivity which is highest for samples with no gallium. The experimental results are analyzed in the Friedel virtual bound state model.