Small-angle neutron scattering (SANS) is an extremely powerful probe of the
vortex state in type IT superconductors. The technique may be further enha
nced by the use of polarised neutrons and the application of the neutron sp
in-echo method. We discuss some recent applications of these techniques to
the study of both conventional and unconventional superconducting materials
. and describe the unique information which SANS can provide on the vortex
state. (C) 2000 Elsevier Science B.V. All rights reserved.