  We performed small-angle neutron scattering (SANS) measurements on the
helimagnetic spinel compound ZnCr2Se4. The ground state of this material is a
multi-domain spin-spiral phase, which undergoes domain selection in a magnetic
field and reportedly exhibits a transition to a proposed spin-nematic phase at
higher fields. We observed a continuous change in the magnetic structure as a
function of field and temperature, as well as a weak discontinuous jump in the
spiral pitch across the domain-selection transition upon increasing field. From
our SANS results we have established the absence of any long-range magnetic
order in the high-field (spin-nematic) phase. We also found that all the
observed phase transitions are surprisingly isotropic with respect to the field
direction.
