Effect of nano-SiC doping on the structure and superconducting properties of Mg(B1−xCx)2

MELONE MAURO; SOBRERO CESAR; TROIANI HORACIO; MALACHEVSKY MARÍA TERESA

Congreso; Congress and General Assembly of the International Union of Crystallography; 2021

Since its discovery, MgB2 is presented as a candidate to replace conventional superconductors in several applications such as SMES and Magnetic Resonators. This possibility is based on its critical temperature (Tc), its low cost, and the possibility of forming cablesby the ?Powder In Tube? (PIT) method. Considerable research has been carried out to optimize the material and the cable conformation [1]. It was determined that the superconducting properties can be improved by inducing changes in the microstructure,with different synthesis methods [2], and/or the crystalline structure, by doping [3]. In this work, two different samples were preparedand characterized to find convenient methods to improve the material and the cables superconducting properties without increasing thecost.The Mg (B1-xCx) 2 samples were prepared starting from Mg and C-doped nano-B powders, with and without the addition of nano-SiC.The compounds were mixed in an agate ball mill inside a glove box. Then, they were compacted into pellets and sintered in a tubefurnace with a circulating controlled Argon atmosphere. The samples were heat treated at two temperatures, 700ºC and 900ºC, fordifferent periods. The specimens were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) (Fig. 1),and SQUID magnetometry. XRD data were refined by the Rietveld method with FullProf [4] as can be seen in Fig. 2. Finally, 700ºCin-situ syntheses were performed on a nano-SiC doped sample at the P61A line in DESY, to study the reaction development.With these techniques, we were able to determine the lattice parameters, the existing phase percentages, the grain sizes, the stressstate, and the Tc. These data together allow for a better understanding of the synthesis parameters and the effect of doping on the phaseformation as a way to improve the superconducting properties of the material.