Single-crystal investigations on the multiferroic material LiFe(WO4)2

The crystal and magnetic structures of multiferroic LiFe(WO4)(2) were investigated by temperature and magnetic-field-dependent specific heat, susceptibility, and neutron diffraction experiments on single crystals. Considering only the two nearest-neighbor magnetic interactions, the system forms a J(1), J(2) magnetic chain, but more extended interactions are sizable. Two different magnetic phases exhibiting long-range incommensurate order evolve at T-N1 approximate to 22.2 K and T-N2 approximate to 19 K. First, a spin-density wave develops with moments lying in the ac plane. In its multiferroic phase below T-N2 LiFe(WO4)(2) exhibits a spiral arrangement with an additional spin component along b. Therefore, the inverse Dzyaloshinskii-Moriya mechanism fully explains the multiferroic behavior in this material. A partially unbalanced multiferroic domain distribution was observed even in the absence of an applied electric field. For both phases only a slight temperature dependence of the incommensurability was observed, and there is no commensurate phase emerging at low temperature or at finite magnetic fields up to 6 T. LiFe(WO4)(2) thus exhibits a simple phase diagram with the typical sequence of transitions for a type-II multiferroic material.

Automated summary

The crystal and magnetic structures of multiferroic LiFe(WO4)(2) were studied through specific heat, susceptibility, and neutron diffraction experiments. Two different magnetic phases with incommensurate order were observed at different temperatures, demonstrating multiferroic behavior. LiFe(WO4)(2) exhibits a simple phase diagram with a sequence of transitions typical for a type-II multiferroic material.