Characterization of cryogenic materials by x-ray absorption methods. [Ta, Zr additions in Nb/sub 3/Sn]
X-ray absorption techniques have in recent years been developed into powerful probes of the electronic and structural properties of materials difficult to study by other techniques. In particular, the extended x-ray absorption fine structure (EXAFS) technique can be applied to a variety of cryogenic materials. Three examples are used to demonstrate the power of the technique. The first is the determination of the lattice location of dilute alloying additions such as Ta and Zr in Nb/sub 3/Sn. The Ta additions are shown to reside predominately in Nb lattice sites, while Zr is not uniquely located at either Nb or Sn sites. In addition to structural information, temperature dependent EXAFS studies can be used to determine the rms deviations of atomic bond lengths, providing information about the temperature dependence of interatomic force constants. For Nb/sub 3/Sn deviations are found from simple harmonic behavior at low temperatures which indicate a softening of the Nb-Sn bond strength. The final example is the study of interfacial properties in thin film systems. This is accomplished by making x-ray absorption measurements under conditions of total external reflection of the incident x-rays. As some examples show, this technique has great potential for studying interfacial reactions, a process used in the fabrication of many superconducting materials.
- Research Organization:
- Brookhaven National Lab., Upton, NY (USA)
- DOE Contract Number:
- AS05-80ER10742; AC02-76CH00016
- OSTI ID:
- 6468481
- Report Number(s):
- BNL-37163; CONF-850814-32; ON: DE86003633
- Resource Relation:
- Conference: Cryogenic engineering conference and international cryogenic materials conference, Boston, MA, USA, 12 Aug 1985
- Country of Publication:
- United States
- Language:
- English
Similar Records
Evidence from EXAFS for Different Ta/Ti Site Occupancy in High Critical Current Density Nb3Sn Superconductor Wires
Ta, Ti and Hf effects on Nb3Sn high-field performance: temperature-dependent dopant occupancy and failure of Kramer extrapolation
Related Subjects
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
NIOBIUM BASE ALLOYS
CRYSTAL LATTICES
TANTALUM ADDITIONS
TIN ALLOYS
ZIRCONIUM ADDITIONS
ABSORPTION SPECTROSCOPY
CRYSTAL STRUCTURE
FINE STRUCTURE
X-RAY SPECTROSCOPY
ALLOYS
NIOBIUM ALLOYS
SPECTROSCOPY
TANTALUM ALLOYS
ZIRCONIUM ALLOYS
360102* - Metals & Alloys- Structure & Phase Studies
656102 - Solid State Physics- Superconductivity- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena- (-1987)