  We report a detailed small-angle neutron scattering (SANS) study of the
skyrmion lattice phase of MnSi under compressive and tensile strain. In
particular, we demonstrate that tensile strain applied in the skyrmion lattice
plane, perpendicular to the magnetic field, acts to destabilize the skyrmion
lattice phase. This experiment was enabled by our development of a versatile
strain cell, unique in its ability to select the application of either tensile
or compressive strain in-situ by using two independent helium-actuated copper
pressure transducers, whose design has been optimized for magnetic SANS on
modulated long-period magnetic structures and vortex lattices, and is compact
enough to fit in common sample environments, such as cryostats and
superconducting magnets.
