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  • 1
    Electronic Resource
    Electronic Resource
    Die Mikrotaktizität von Polyacrylestern (1978)
    Springer
    Colloid & polymer science 256 (1978), S. 620-620 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01639370
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  • 2
    Electronic Resource
    Electronic Resource
    Large magnetoresistivity of sputtered Al-(O or N)-Bi alloys (1988)
    Springer
    Journal of materials science 23 (1988), S. 2355-2360 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Application of the sputtering technique to (Al2O3)xBi100−x and (AIN)x Bi100−x (x = 0 to 100%) has been found to result in the formation of a duplex material consisting of hexagonal bismuth particles dispersed finely and homogeneously in amorphous AlxOy and AlxNy matrices. The particle size and interparticle distance of the bismuth phase were about 5 to 140nm and 5 to 35 nm. The duplex alloys have high electrical resistivities ranging from 1.82 × 103 to 3.16 × 105 μΩcm combined with a negative temperature-dependent resistivity of 148 to 342% of ϱ273. Furthermore, all the Al-O-Bi and Al-N-Bi alloys have been found to exhibit a positive magnetoresistive change and the maximum value, Δϱ(H), at 4.2 K and 7.5T reaches 5.85 × 104 μΩ cm for (Al-O)65.7Bi34.3 and 1.99 × 105 μΩcm for (Al-N)69.7 Bi30.3. The large magnetoresistivities are probably due to the unique sputtered structure consisting of metallic bismuth particles with a long mean free path of electrons embedded finely and homogeneously in amorphous AlxOy or AlxNy matrix, resulting in the large difference of the relaxation times (different mobilities) of electron carriers. It has thus been demonstrated that the oxide- or nitride-based composite materials exhibiting large magnetoresistivities, which cannot be achieved in metallic composite materials, are obtained by sputtering simultaneously Al2O3 or AIN and bismuth which is immiscible to aluminium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01111887
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  • 3
    Electronic Resource
    Electronic Resource
    Critical current density and electrical resistivity of highT c superconductors in the La-Sr-Cu-O system prepared by the solidification method (1987)
    Springer
    Journal of materials science 6 (1987), S. 990-992 
    Details
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01729894
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  • 4
    Electronic Resource
    Electronic Resource
    Effect of annealing on the superconducting properties of two amorphous alloys: Nb70Zr15Si15 and Zr85Si15 (1984)
    Springer
    Journal of materials science 19 (1984), S. 2719-2730 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The changes in the superconducting and electronic properties of amorphous Nb70Zr15Si15 and Zr85Si15 alloys with annealing were examined with an aim to evaluate the effect of structural relaxation on the superconductivity of metal-metalloid type amorphous alloys.T c rises once from 3.99 to 4.42 K on annealing at temperatures below about 473 K for the Nb-Zr-Si alloy and from 2.71 to 2.75 K at temperatures below about 373 K for the Zr-Si alloy, and with further rising annealing temperature,t d, lowers monotonically to a final relaxed value (≃3.15 K for Nb70Zr15Si15 and ≃2.49 K for Zr85Si15), which is independent of the previous thermal cycling. These results indicate that the thermal relaxation of an amorphous phase occurs through at least two stages. The lowering ofT c occurs exponentially witht d, and an activation energy for the relaxation process and the frequency of jump over the barrier were estimated to be about 2.03 eV and 2.4×1014 sec−1 for Nb70Zr15Si15 and about 1.28 eV and 1.2×1011 sec−1 for Zr85Si15, respectively. The high frequencies indicate that the relaxations occur more or less independently of each other in a non-co-operative manner. The dressed density of electronic states at the Fermi level,N(E f) (1+λ), which was calculated from the measured values ofρ n and (dH c2dT)Tc, exhibited a similar annealing temperature dependence to that ofT c. From this the change inT c on thermal relaxation was interpreted as due to the changes in λ and/orN(E f). From the depressions ofJ c(H) and fluxoid pinning force on annealing in a temperature range of 473 to 873 K, it was concluded that the structural relaxation from a less homogeneous quenched-in state to a homogeneous stable state occurred on the scale of coherence length (≃7.5 nm) during the annealing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00550830
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  • 5
    Electronic Resource
    Electronic Resource
    Correlation between structural relaxation enthalpy and superconducting properties of amorphous Zr70Cu30 and Zr70Ni30 alloys (1985)
    Springer
    Journal of materials science 20 (1985), S. 2323-2334 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The anneal-induced change in the superconducting properties together with the irrecoverable relaxation enthalpy (ΔH i,exo) and recoverable relaxation enthalpy (ΔH r,endo) of amorphous Zr70Cu30 and Zr70Ni30 alloys was examined. The increase in Δi,exo and the degradation ofT c progress logarithmically with annealing timet a in a temperature range of 373 to 523 K. The activation energy and the attempted frequency were respectively estimated to be 1.5eV and 6.6 × 1013 sec−1 for the increase in ΔH i,exo and 1.5eV and 1.9×1014 sec−1 for the degradation ofT c. The recoverable structure relaxation exerts little effect onT c. Based on the agreement between the kinetic parameters for the changes of ΔH i,exo andT c, it appears that the degradation ofT c on annealing is associated with the irrecoverable structural relaxation as a result of the annihilation of frozen-in defects and the topological and compositional atomic rearrangement. The values of the attempted frequency being of the order of Debye frequency suggest that the irrecoverable structural relaxation processes occur more or less independently from each other. The dressed density of electronic states at the Fermi level,N(E f)(1+λ), determined from the measured values ofρ n and -(dH c2/dT)T c using GLAG (theory), was found to have a similar annealing dependence to that ofT c. The degradation ofT c by the irrecoverable relaxation was thus inferred as resulting from the decrease inλ due to the decrease inN(E f) and the increases inM and ω. Furthermore, the irrecoverable structural relaxation resulted in a significant depression of fluxoid pinning force and was interpreted as due to an enhanced structural homogeneity on the scale of coherence length.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00556062
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  • 6
    Electronic Resource
    Electronic Resource
    Preparation of nickel-based amorphous alloys with finely dispersed lead and lead-bismuth particles and their superconducting properties (1986)
    Springer
    Journal of materials science 21 (1986), S. 260-268 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The application of the melt-quenching technique to Ni-Si-B-Pb, Ni-P-B-Pb, Ni-Si-B-Pb-Bi and Ni-P-B-Pb-Bi alloys containing immiscible elements such as lead and bismuth has been tried and it has been found to result in the formation of a new type of material consisting of fine fcc Pb or hcp ɛ(Pb-Bi) + bct X(Pb-Bi) particles dispersed uniformly in the nickelbased amorphous matrix. The particle size and interparticle distance were 1 to 3 and 1 to 4 µm, respectively, for the lead phase, and less than 0.2 to 0.5 µm and 0.2 to 1.0 µm for the Pb-Bi phase. The uniform dispersion of such fine particles into the amorphous matrix was achieved in the composition range below about 6at% Pb and 7at% (Pb + Bi). Additionally, these amorphous alloys have been found to exhibit a superconductivity by the proximity effect of f c c Pb or ɛ(Pb-Bi) superconducting particles. The transition temperatureT c was in the range 6.8 to 7.5 K for the Ni-Si(or P)-B-Pb alloys and 8.6 to 8.8 K for the Ni-Si (or P)-B-Pb-Bi alloys. The upper critical fieldH c2 and the critical current densityJ c for (Ni0.8 P0.1 B0.1)95 Pb3 Bi2 at 4.2 K were, respectively, about 1.6T and of the order of 7 X 107 A m−2 at zero applied field. Melt quenching of amorphous phase-forming alloys containing an immiscible element has thus been demonstrated, enabling us to produce amorphous composite materials exhibiting unique and useful characteristics which cannot be obtained in homogeneous amorphous alloys.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01144730
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  • 7
    Electronic Resource
    Electronic Resource
    Superconducting and electrical properties of amorphous zirconium-transition metal binary alloys (1986)
    Springer
    Journal of materials science 21 (1986), S. 1258-1268 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In order to clarify the compositional effect on the superconductivity of zirconium-transition metal (M) binary amorphous alloys, the superconducting properties and electrical resistance of the alloys were examined as functions of the concentration, group number and periodicity of the M elements.T c for Zr75M25 alloys rises in the order Ru 〉 Rh 〉 Ir 〉 Co 〉 Os 〉 Ni 〉 Pt 〉 Cu 〉 Pd 〉 Fe 〉 Au, i.e. as the group number decreases when the periodicity belongs to the 5th period, and with decreasing M content for Zr100−X M X alloys. The highT c attained in the present work is 4.55 K for Zr80Rh20, 4.38 K for Zr75Rh25 and 4.47 K for Zr75Ru25. The temperature gradient of the upper critical magnetic field (H c2) near the transition temperature (T C) tends to increase with increasing zirconium content, and the resistive state due to the flux flow phenomena appears in a wide sweeping field. Following the sharp and large decrease of the flux flow resistance due to a peak effect, the resistance recovers sharply nearH c2. The peak effect was found to occur more distinctly for the alloys containing a magnetic element of iron or cobalt, probably because of the suppression of the pair-breaking effect due to magnetic scattering by the application of the high field nearH c2. The dominating factor for the compositional effect onT C is inferred to originate from the variation ofλ throughω for Zr100−x M X alloys and from that of λ through N(Ef) for Zr75M25 alloys. Additionally, it has been found for the Zr-M amorphous alloys that the electrical resistivityρ(T) exhibits a maximum value at temperature ranging from 2T C to 3T C, suggesting that the hump phenomenon in ρ(T) appeared through the generation of the superconducting fluctuations. The temperature coefficient of resistivity (tcr) defined by 1/R250(dR/dT) shows negative values ranging from 1.05×10−4 to 1.75×10−4 K −1 andT C was found to rise through the increase inλ with the increase in the negative value of the tcr.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00553260
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  • 8
    Electronic Resource
    Electronic Resource
    Microstructure and superconducting properties of melt-quenched insoluble Al-Pb and Al-Pb-Bi alloys (1987)
    Springer
    Journal of materials science 22 (1987), S. 123-131 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In order to obtain aluminium-based superconducting alloys including finely dispersed lead or Pb-Bi particles, the application of the melt-quenching technique has been tried for Al-Pb, Al-Si-Pb and Al-Si-Pb-Bi alloys containing immiscible elements such as lead and bismuth. It has been found to result in the preparation of superconducting materials consisting of fcc Pb or h c p ε(Pb-Bi) particles dispersed finely and densely in the aluminium-based matrix in each composition range below about 2 at % Pb for Al-Pb alloys and 5 at % Pb or (Pb + Bi) for (Al0.9 Si0.1)100−x Pb x and (Al0.9Si0.1)100−x (Pb0.6Bi0.4) x alloys. The particle size and interparticle distance were ∼ 40 nm and 40 to 100 nm, respectively, within the grains, and ∼ 100 nm and below ∼ 30 nm, respectively, at the grain boundaries for the lead phase in Al98 Pb2 alloy. Particle size was ∼ 15 to 60 nm and interpartide distance 30 to 60 nm for the Pb- Bi phase in (Al0.9 Si0.1)95(Pb0.6 Bi0.4)5 Transition temperature,T c was 4.16 K for Al98Pb2, 3.94K for (Al0.9Si0.1)95 Pb5 and 7.75 K for (Al0.9Si0.1)95(Pb0.6Bi0.4)5. The upper critical magnetic field,H c2, and critical current density,J c, for (Al0.9Si0.1)95(Pb0.6Bi0.4)5 were 0.22 T at 4.2 K and 1.67 × 107 Am−2atzeroappliedheld and 4.2 K. The appearance of the superconductivity for the aluminium -based alloys was interpreted as due to the formation of superconducting percolation path along the tangled dislocations, sub-boundaries and/or grain boundaries where Pb and Pb-Bi phases precipitated preferentially.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01160560
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  • 9
    Electronic Resource
    Electronic Resource
    High-field superconductivity in Al-O-Pb and Al-O-Pb-Bi sputtered films (1987)
    Springer
    Journal of materials science 22 (1987), S. 4362-4368 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The sputter-quenched Al x O y alloys containing lead and bismuth elements, which are insoluble to aluminium; have been found to exhibit a remarkably enhanced upper critical field,H c2, which is higher by about 6 to 66 times than those of pure lead metal and Pb60Bi40 alloy. The sputtered structure consists of amorphous Al x O y and f c c lead or h c pε (lead-bismuth) phases. The lead andε phases disperse homogeneously in the amorphous matrix and their particle sizes and interparticle distances are about 10 to 20 nm and 5 to 20 nm, respectively, for lead andε particles. The superconducting transition temperature,T c, upper critical magnetic field,H c2, at 4.3 K, and residual resistivity at 10 K are 7.74 K, 3.3 T and 2.09 × 105μΩcm, respectively, for (Al-O)92.8 Pb7.2 and 7.45 K, 8.2 T and 1.70 × 106μΩ cm, respectively, for (Al-O)86.2(Pb0.6 Bi0.4)13.8. The remarkable enhancement ofH c2 is interpreted as being mainly due to a remarkable decrease of the coherence length resulting from a large reduction of the effective mean free path of electrons. Additionally, the fluxoid pinning force under applied field has also been markedly enhanced for the duplex structure films than for sputtered lead film, probably because of the change of the dispersed lead phase into a type-II superconductor and an effective fluxoid pinning action at the interface between Al x O y and fine lead particles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01132030
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  • 10
    Electronic Resource
    Electronic Resource
    Anomalous electrical resistive behaviour of Al-O-Pb sputtered alloys (1987)
    Springer
    Journal of materials science 22 (1987), S. 2063-2068 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Application of the sputtering technique to (Al-O) x Pb100-x alloys containing an immiscible lead element has been found to result in the formation of a duplex material consisting of f cc lead particles dispersed in an amorphous Al x O y oxide matrix. The particle size and interparticle distance of the lead phase were about 10 to 50 nm and 10 to 40 nm, respectively. The Al-O-Pb alloys have been found to exhibit an extremely high electrical resistivity (ϱ), e.g., 4.06 x 106 μΩ cm for (Al-O)87.5 Pb12.5 at 273 K, as well as a large positive temperature-dependent resistivity reaching 92% Of ϱ273. The peculiar resistivity behaviour was interpreted by assuming the mechanism that only the lead phase embedded in AlxOy matrix contributes to electrical conductivity and the mobility of lead electrons is greatly reduced in the intervening oxide region among lead phases. It has thus been demonstrated that the composite material exhibiting peculiar characteristics, which cannot be achieved in metallic composite materials, is obtained by simultaneously sputtering oxide and an insoluble metallic element.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01132940
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