Upper critical field and related properties of superconducting amorphous alloys Zr--Si
The upper critical field H/sub c/2 has been measured for the superconducting amorphous alloys Zr/sub 100-x/Si/sub x/ with x = 13, 15, and 17 over a wide temperature range down to 50 mK. Measurements for related properties, such as the depinning current density J/sub p/, pinning force density F/sub p/, and flux flow resistivity rho/sub f/, reveal that these systems are well characterized as typically soft and dirty type II superconductors with an extremely low J/sub p/ of 1 A/cm/sup 2/ and F/sub p/ of 1.5 x 10/sup 4/ N/m/sup 3/ at h(equivalentH/H/sub c2/) = 0.5 and t(equivalentT/T/sub c/) = 0.5. The temperature dependence of H/sub c2/ is well fitted by a curve of the Werthamer-Helfand-Hohenberg theory with Maki parameter ..cap alpha.. = 1.7--1.5 and spin-orbit interaction parameter lambda/sub so/ = 1--2.4. These results indicate that the Pauli spin-paramagnetic effect plays an important role in the low-temperature behavior of H/sub c2/ in these low-T/sub c/ and high-H/sub c2/ amorphous superconductors. Corrections of the electron-phonon coupling (lambda/sub ep/ = 0.6) to the Pauli spin-paramagnetic limiting field lead to a reduced importance of the spin-orbit interaction effect, with lambda/sub so/ less than 1.0 A discussion is given of the structural inhomogeneities in an amorphous phase, which are sensitively reflected in the strength of the fluxoid line pinning interaction (J/sub p/, F/sub p/) and are intimately related to the nonintrinsic anomaly, observed in many amorphous alloys, that H/sub c2/ values.
- Research Organization:
- The Research Institute for Iron, Steel and Other Metals, Tohoku University, Sendai, Japan
- OSTI ID:
- 6694765
- Journal Information:
- J. Low Temp. Phys.; (United States), Vol. 55:5
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
SILICON ALLOYS
CRITICAL FIELD
ZIRCONIUM BASE ALLOYS
AMORPHOUS STATE
CURRENT DENSITY
ELECTRON-PHONON COUPLING
EXPERIMENTAL DATA
MAGNETIC FLUX
SUPERCONDUCTIVITY
TEMPERATURE DEPENDENCE
ULTRALOW TEMPERATURE
ALLOYS
DATA
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
INFORMATION
MAGNETIC FIELDS
NUMERICAL DATA
PHYSICAL PROPERTIES
ZIRCONIUM ALLOYS
360104* - Metals & Alloys- Physical Properties
656102 - Solid State Physics- Superconductivity- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena- (-1987)