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T c anisotropy and texture of fine niobium wire and foil
Author(s) -
Shamrai V. F.,
Galperovich D. Ya.,
Efimov Yu. V.,
Korzhakova T. V.,
Babareko A. A.,
Grechkov V. I.,
Savelyeva M. E.
Publication year - 1988
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.2170230516
Subject(s) - foil method , niobium , texture (cosmology) , anisotropy , materials science , metallurgy , crystallography , condensed matter physics , composite material , optics , physics , chemistry , computer science , image (mathematics) , artificial intelligence
Texture of surface and inner layers of cold‐deformed (> 90%) niobium wire (diameter — 0.5 mm) and foil (thickness — 40 μm) was studied immediately after deformation followed by layer‐wise etching of near‐the‐surface layers and the annealing effect in 0.001 and 0.00001 Pa vacuum on texture was found. Axis and inner plane textures of cold‐deformed niobium wire and foil, respectively, are typical of bcc lattice metals. The surface layer of fine wire subjected to considerable cold deformation possesses so‐called cylindrical plane deformation texture {100}〈011〉 (main) and {111}〈011〉 (additional). Surface layer of high deformed niobium foils is characterized by the shear texture {110}〈001〉. Presence of delineated texture and its maintainance during annealing (with changing ratio of individual components) causes the T c anisotropy in fine niobium materials. T c anisotropy is caused by different orientations of magnetic fields and directions of currents used for measurements by resistive and inductive methods with respect to the directions of prefered crystallographic orientation of wire axis and foil plane. The T c values of pure niobium wire and foil measured by the resistive method are 0.1–0.3 K higher than the standard (9.2–9.3 K).