Modem materials superconductors

In materials analysis, laser ablation has been applied to almost all fields of modem materials. For glasses, high-purity optical materials (e.g. CaF2), ceramics, semi- and superconductors, polymers, high-purity metals and alloys, the heterogeneity of the material, trace element concentrations and elemental distributions have been measured. In addition, this method has been used for the investigation of trace element composition of concrete, radioactive waste and radioactive materials, the characterization of steel inclusions and the determination of the composition and thickness of layered systems. 

Oxides play many roles in modem electronic technology from insulators which can be used as capacitors, such as the perovskite BaTiOs, to the superconductors, of which the prototype was also a perovskite, Lao.sSro CutT A, where the value of x is a function of the temperature cycle and oxygen pressure which were used in the preparation of the material. Clearly the chemical difference between these two materials is that the capacitor production does not require oxygen partial pressure control as is the case in the superconductor. Intermediate between these extremes of electrical conduction are many semiconducting materials which are used as magnetic ferrites or fuel cell electrodes. The electrical properties of the semiconductors depend on the presence of transition metal ions which can be in two valence states, and the conduction mechanism involves the transfer of electrons or positive holes from one ion to another of the same species. The production problem associated with this behaviour arises from the fact that the relative concentration of each valence state depends on both the temperature and the oxygen partial pressure of the atmosphere. 

---