Neutron induced disorder in superconducting A-15 compounds

The effect of high energy neutron (E>1 MeV) irradiation at 60°C on the superconducting critical temperature, T
c
, the upper critical field, H
c2
, the lattice parameter, a
o
, and the degree of Long Range Order has been measured for Nb and V based A-IS superconducting compounds. Large reductions in T
c
, and H
c2
are observed for fluences up to 5.0 × 10
¹⁹
n/cm
²
. For Nb
3
Al a
o
increases and the degree of Long Range Order is significantly reduced as T
c
is depressed. The results are discussed in terms of atomic ordering in the A-15 structure.