PDF Publication Title:
Text from PDF Page: 034
1.2 Physical properties of the RNiO3 system Figure 1.8: Distribution of electronic cloud in eg and t2g orbitals. - eg orbitals are symmetric with respect to all x, y, z axes. On the other hand t2gorbitals show symmetry to only one axis for each orbital (51) It was shown that even rhombohedral NdNiO3 exhibits MI transition with a large hysteresis (95). Qualitatively the behaviour does not change with respect to the ’temperature direction’, however a large hysteresis is observed and does not depend on the rate of temperature change (95). What is more, the semiconductor region is not totally homogeneous. Two regions with different activation energy were identified in NdNiO3. The one with higher activation energy was ascribed to a state where the nickelate is an intrinsic semiconductor and when it enters the second region at low temperature - it becomes an extrinsic semiconductor. Vassiliou investigated the influence of the preparation method on the resis- tivity of the NdNiO3 to study the effect of grain size. The samples were however polycrystalline and no influence on resistivity of different pressure and tempera- ture conditions were observed. However, he still accounts the crystal structure to be an important factor. Results of Lacorre et al. show that orthorhombic nickelates (Pr, Nd, Sm) undergo MI transition that is more sharp (few orders of magnitude drop in resis- tance in comparison with factor of 5 for rhombohedral phase) but the hysteresis is smaller(66). Based on Bond Valence Model calculations for RNiO3 Garc ́ıa-Mun ̃oz et al. suggested a R3+, Ni3+ and O2− first approximation of the electronic structure of the compounds. The distances Ni-O also suggested that it is highly unlikely that in these compounds holes are selectively localized on oxygen atoms. It is also worth to mention the theory formulated by Zaanen, Savatzky and 13PDF Image | Investigation of metal-insulator transition in magnetron sputtered samarium nickelate thin films
PDF Search Title:
Investigation of metal-insulator transition in magnetron sputtered samarium nickelate thin filmsOriginal File Name Searched:
Bilewska_Investigation_of_metal_insulator_transition_in_magnetron_sputtered_samarium.pdfDIY PDF Search: Google It | Yahoo | Bing
Sulfur Deposition on Carbon Nanofibers using Supercritical CO2 Sulfur Deposition on Carbon Nanofibers using Supercritical CO2. Gamma sulfur also known as mother of pearl sulfur and nacreous sulfur... More Info
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
| CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com | RSS | AMP |