Abstract
We investigate the effects of Co2+ doping on the magnetism, ferroelectricity, and magnetoelectric coupling in the Mn1-xCoxWO4(0≤x≤0.1). The lower Co doping (at x≤0.05) suppresses the commensurate collinear antiferromagnetic phase (AF1 phase) and stabilizes the ferroelectric phase down to T=2K. For higher Co substitution levels x=0.06 and 0.07, the ferroelectric polarization P reaches a peak at T=10.2K and T=8.7K, respectively, and decreases to nonzero (measured at T=2K) with further cooling, which can be attributed into a continuous rotation of the spiral plane driven by the small change in temperature. The polarization P at x=0.1 increases monotonically with cooling, which suggests the orientation of the spin helix unchanged. Ferroelectric polarization P reverses synchronously with the applying the cyclic oscillation external magnetic field and suggests that the polarization P is strongly coupled with the magnetism in the Mn0.95Co0.05WO4 sample.