Relationship between magnetic structure and ferroelectricity of systems with CuO2 ribbon chains

Results of experimental studies carried out by various methods on systems with CuO2 ribbon chains are presented. For LiVCuO4, which was found to have helimagnetic and ferroelectric simultaneous transitions (multiferroic transitions), the relationship between the magnetic structure and the ferroelectricity is described in detail by showing their magnetic field dependences. For Li2ZrCuO4, NMR studies have revealed that the system has ac-helical magnetic structure. However, we have not observed the ferroelectricity in this ordered phase. This result suggests that there may exist the antiferro-type ordering, for example, of the helical axis vectors, of the CuO2 chains. Several new findings are also shown on the magnetic and dielectric properties of other ribbon chain systems, LiVCuO4, Li2ZrCuO4, LiCu2O2 and NaCu2O2 and a related system Na2Cu3(GeO3)4.

Figure optionsDownload as PowerPoint slide