Abstract:
Multiferroic and magnetoelectric materials have attracted renewed attention since the magnetic orders breaks the spatial inversion symmetry and give rise to a ferroelectric state with a macroscopic polarization[1].The frustrated nature of the magnetic state in multiferroic MnWO4 is the reason [2] for its extreme sensitivity of the ferroelectric/magnetic orders to small perturbations in form of magnetic and electric fields, external pressure, and chemical substitutions[3-5]. Using neutron diffractions, we have characterized the effect of cobalt substitution on the magnetic configuration and corresponding multiferroic behavior[6]. A complex phase diagram with multiple polarization flops upon increasing Co content is observed. Two critical concentrations separate the multiferroic phases with distinct spin structures and orientation of the ferroelectric polarizations. With application of hydrostatic pressure, we further examine the evolution of spin structures at various Co concentrations. Our neutron scattering results provide critical understanding of the pressure induced polarization-switching in the doped sample.
[1] T. Kimura et al., Nature 426, 55 (2003).
[2] F. Ye et al., Phys. Rev. B84, 179901 (2011).
[3] R. P. Chaudhury et al., Phys. Rev. B83, 014401 (2011).
[4] F. Ye et al., Phys. Rev. B78, 193101 (2008).
[5] N. Poudel et al., Phys. Rev. B89, 054414 (2014).
[6] F. Ye et al., Phys. Rev. B86, 094429 (2012).
