Features of Optical Properties and the Electronic Structure of Nanostructured Oxides of 3d-Metals

Abstract

Features of the optical properties of nanostructured strongly correlated oxides CuO, Y3Fe5O12, and FeBO3 in a wide range of energies, which includes both the fundamental absorption region, low-energy electron excitations, and phonon modes have been investigated by methods of optical spectroscopy. Absorption and reflection spectra, Raman spectra, and ellipsometry measurements are carried out on the samples of oxide nanostructured ceramics. High-density nanoceramics were prepared by shock-wave loading and high pressure torsion methods from coarse-grain oxide powders. Strong smearing of the fundamental absorption edge is revealed for all nanoceramics. Anomalous red shift of the absorption edge Eg is found in CuO nanooxide. The features of the optical functions in nanooxides of 3d-metals may be attributed to high defectiveness of nanooxides, peculiarities in the electronic structure of strongly correlated oxides and their tendency to electronic phase separation.

Advanced Photocatalysts for CO2 Conversion by Severe Plastic Deformation (SPD)

“…The inducing ultra-SPD [ 51 ] together with fast dynamic diffusion [ 52 , 53 ] introduces the HPT method as a unique path to mechanically synthesize new materials even from immiscible systems [ 54 , 55 ]. Due to these unique features of HPT, the method was even used for the process and synthesis of hard and brittle ceramics, but the number of publications on ceramics is quite limited despite the high potential of these materials for various applications [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 ]. Published studies regarding ceramics processed or synthesized by HPT are presented in Table 1 , although there are other classic publications on HPT processing of ceramics mainly by physicists and geolog...…”