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We report an original procedure for the elaboration of very high-quality single crystals of superconducting HgBa2Ca2Cu3O8+δmercury cuprates. These single crystals are unique, with very high-quality surface paving the way for spectroscopic, transport, and thermodynamic probes in order to understand the hole-doped cuprate phase diagram. Annealing allows one to optimize Tcup to Tcmax= 133 K. The superconductivity transition width of about 2 K indicates that they are homogeneous. We show for the first time that, with adequate heat treatment, Hg-1223 can be largely underdoped and its doping level controlled. Importantly, the crystal structure was studied in detail by single-crystal X-ray diffraction, and we have identified the signature of the underdoping by a detailed sample characterization and micro-Raman spectroscopy measurements.

Reactive high energy ball-milling has known a growing interest from both fundamental and applied point of view. We focus here on the specific system Fe-Y2O3 metal-oxide nanocomposite because of its potential application to the synthesis of oxide dispersion strengthened steels, which are promising materials for nuclear applications. YFe3 and Fe2O3 were ball-milled during different milling durations in the stoichiometric proportions defined by the chemical reaction 2 YFe3 + Fe2O3 → 8 Fe + Y2O3. The obtained milled powder was characterized by XRD, SEM, TEM and their thermal behaviour was investigated by DTA. Through those characterizations, a Mechanically induced Self-propagating Reaction (MSR) was observed and several steps in the ball-milling process were identified: mixing of reactants, chemical reaction propagation, amorphization and refinement of the microstructure. The role of the milling intensity was also examined.