Synthesis and physical properties of MSr2RCu2O8 and MSr2(R,T)2Cu2O10 (M = Nb, Ta, Ru; R = Nd, Sm, Eu, Gd; T = Ce, Th) compounds

Abstract

The aim of this scientific project is to prepare high-quality polycrystalline samples of RSr2MCu2O8 (1212) and MSr2 (R, T) 2Cu2010 (1222) (T = Ce, Th, R = Nd, Gd, M = Nb, Ta, Ru) compounds. The synthesis of these materials will be made by two different routes: (I) a mixture of oxides, and (II) the method of sol-gel precursors. To optimize the oxygen content and range of Ce/Th doping, heat treatments will be performed in the flow and pressure of O2. The characterizations of the samples will be made using techniques of X-ray diffraction, electrical resistivity, and magnetic susceptibility. The X-ray diffraction is used for structural characterization, enabling monitoring of the evolution of crystallographic parameters for different heat treatments to which these compounds will be subjected. The physical properties of the materials, such as magnetic susceptibility and electrical resistance, will be also investigated. The first will be conducted using a SQUID magnetometer and the second on a workstation able to collect data from electrical resistivity r (T) at temperatures down to T ~ 10 K. The physical properties will be discussed by varying the content of Ce and Th in this family of superconducting materials.(AU)