  We have carried out a systematic study on the effect of Cu doping on nuclear,
magnetic, and dielectric properties in Mn$_{1-x}$Cu$_{x}$WO$_4$ for
${0}\leq{x}\leq{0.19}$ by a synergic use of different techniques, viz, heat
capacity, magnetization, dielectric, and neutron powder diffraction
measurements. Via heat capacity and magnetization measurements we show that
with increasing Cu concentration magnetic frustration decreases, which leads to
the stabilization of commensurate magnetic ordering. This was further verified
by temperature-dependent unit cell volume changes derived from neutron
diffraction measurements which was modeled by the Gr\"{u}neisen approximation.
Dielectric measurements show a low temperature phase transition below about
9-10 K. Further more, magnetic refinements reveal no changes below this
transition indicating a possible spin-flop transition which is unique to the Cu
doped system. From these combined studies we have constructed a magnetoelectric
phase diagram of this compound.
