Významné výsledky oddělení 12

Characteristic frequencies of nanoscale polar fluctuations have been resolved by means of neutron diffuse scattering measurements on a Sr_0.61Ba_0.39Nb₂O₆ single crystal in the MHz-GHz frequency region.

Phase-field simulations demonstrate that the polarization order-parameter field in the Ginzburg-Landau-Devonshire model of rhombohedral ferroelectric BaTiO₃ allows for an interesting linear defect, stable under simple periodic boundary conditions. This linear defect, here called the Ising line, can be described as an about 2-nm-thick intrinsic paraelectric nanorod acting as a highly mobile borderline between finite portions of Bloch-like domain walls of opposite helicity. Celý text »

The ultra-broadband dielectric spectroscopy is particularly useful for studying dielectric–conductor nanocomposites, particularly near the electrical percolation threshold. Theoretically, we have studied the spectra of effective dielectric response of such composites using several models within the effective medium approximation [1]. Celý text »

Time-resolved terahertz spectroscopy provides a useful insight into charge carrier motion in nanostructured semiconductors: it provides a contact-free access to local response of charge carriers inside nanostructures averaged over macroscopic volume of a sample. This is a very pertinent quantity for many applications of disordered materials which still have a larger potential than perfectly aligned nanostructures.