| 초록 |
The (00l)C oriented conductive CaRuO3-η (CRO) thin films with typical thickness of 200nm were fabricated on (100) Si substrate by radio frequency magnetron sputtering and successively heat-treated in atmosphere. According to their deposition temperature (TD) and annealing temperature (TA), they exhibit different transport properties and electronic states in addition to the diverse microstructure. A simple model, which assumes a lattice contraction of pseudocubic unit-cell, allowed us to account for the variation of transport properties and electronic states depending on their TD and TA with an abrupt change in microstructure. The temperature dependent resistivity (R-T) curve, x-ray photoelectron spectroscopy (XPS), and x-ray absorption near edge structure (XANES) data indicated that the variation of transport property is more related to the change in the oxidation state between Ca2+ and O2- according to our simple model. It is believed that the shrinkage of unit cell volume induces an expansion of phi* bandwidth formed by Ca-O bond strengthening, linking the conduction path of RuO6 octahedra networks and leading to the more metallic characteristics. |
