Accession Number:

AD0671944

Title:

SUPERCONDUCTING PROPERTIES OF TRANSITION METAL CARBIDES AND NITRIDES.

Descriptive Note:

Final rept. 1 Oct 65-1 Dec 67,

Corporate Author:

MINNESOTA UNIV MINNEAPOLIS SCHOOL OF MINERAL AND METALLURGICAL ENGINEERING

Personal Author(s):

Report Date:

1968-02-15

Pagination or Media Count:

122.0

Abstract:

Tc, Hc, and Jc measurements were made as a function of alloying composition, deviations from stoichiometry, and crystal structure for several carbides and nitrides. Tcs as high as 17K and upper critical fields of over 136kOe were found for several ternary compositions. Hc2 was found to be limited by the k1 term in the GLAG theory. Thus, the upper critical field depends on the product of the Tc, normal resistivity, and coefficient of electronic specific heat. Methods other than powder metallurgy were developed for preparing carbides and nitrides. Thin films of nitrides were prepared by reactive sputtering. Critical fields-critical current characteristics were very promising for thin-film solenoid applications. Measurement was made of low temperature heat capacities for molybdenum, niobium, and tantalum carbides as a function of crystal structure and composition, and determination was made of electron-phonon interaction parameters and unrenormalized densities of states. Evaluation of proposed bonding models for carbides and nitrides was made on the basis of low temperature heat capacities measurements.

Subject Categories:

  • Electricity and Magnetism

Distribution Statement:

APPROVED FOR PUBLIC RELEASE