Near-edge X-ray absorption spectroscopy (NEXAFS) is an essential analytical tool in material science. Combining NEXAFS with scanning transmission X-ray microscopy (STXM) adds spatial resolution and the possibility to study individual nanostructures. In this work, we described a full-field transmission X-ray microscope (TXM) that generates high resolution, large-area NEXAFS data with a collection rate two orders of magnitude faster than is possible with STXM. The TXM optical design combines a spectral resolution of E/DE5 13104 with a spatial resolution of 25 nm in a field of view of 15–20 mm and a data acquisition time of ∼1 s. As an example, we present image stacks and polarization-dependent NEXAFS spectra from individual anisotropic sodium and protonated titanate nanoribbons ((Na,H)TiNRs, HTiNRs)). Combined NEXAFS-TXM technique has the advantage that one image stack visualizes a large number of nanostructures and therefore already contains statistical information. This new high-resolution NEXAFS-TXM technique opens the way to advanced nanoscale science studies.
COBISS.SI-ID: 25317671
The above Chemical Society Reviews paper was prepared following the invitation by the CSR Editors. This review paper summarized current state of the art in the field of physical properties of icosahedral and decagonal quasicrystals (electrical resistivity, thermoelectric power, Hall coefficient and thermal conductivity), giving a survey of the experimental results and theoretical models. Large part of the paper is based on the results obtained in the Author's laboratory at the J. Stefan Institute.
COBISS.SI-ID: 26118439
Neutron diffraction measurements at 53 mK (T/TN ~ 1/200) showed the absence of naively expected transition into circular helical magnetic state. Muon spin relaxation measurements have further revealed that in spite of long range ordering magnetic ground state the spin dynamics does not freeze out even in the limit of T → 0. They have shown that amplitude-modulated magnetic structures serve as model systems for the contradictory coexistence of long-range order and persistent spin dynamics.
COBISS.SI-ID: 26300711
Via direct measurements we show that the refrigerant capacity of PLZT ceramics and ferroelectric polymer films exceed several times all previously known materials including the magnetocaloric materials. By using a high resolution calorimetry we proved the existence of the phase transition line between the glassy and ferroelectric phase of relaxor ferroelectrics and explained the anisotropy of criticality in these systems. We described the way how to control the temperature profile of the thermomechanical response in liquid crystal elastomers via different physical parameters such as mechanical fields and state of order during the crosslinking procedure. We show that highly confined liquid crystals exhibit a crossover in the dimensionality of the problem.
COBISS.SI-ID: 25971495
Temperature-concentration (T-phi) phase diagram of binary confined liquid crystal 7AB was determined. The nonequilibrium concentration of cis-isomers was controlled by illumination with UV light. Establishment of equilibrium state with all trans-isomers was monitored in-situ via quadrupole-perturbed nuclear magnetic resonance of 2H. Isotropic-nematic phase coexistence regions were determined by analyzing the time-dependences of the spectra. Moreover, isonematic lines (constant nematic order parameter) were identified in the phase diagram.
COBISS.SI-ID: 25964071