Al doping influence on crystal growth, structure and superconducting properties of Y(Ca)Ba2Cu3O7−y whiskers

X-ray crystal structures of Al-doped (Y,Ca)Ba2Cu3O7−ywhiskers

“…These results extend the previous observations on electrical resistivity by Calore et al (2013), showing that the combined action of Al and Ca can modify the superconducting properties in a positive way compared with the action of Ca only, if the content of vicariant Al is about 0.06. On the other hand, the fact that higher contents (i.e.…”

“…The cell parameters (Table 2) show a gradual increase of the a axis and a gradual approach of the a-and b-axis values, equal in the tetragonal cell, therefore confirming both the values and the general trend reported in recent studies (Calore et al, 2013). The variation of cell parameters reflects the gradual appearance of the O5 ion inside the unit cell along the a axis (see Fig.…”

“…It is worth noticing that the Al content measured for each crystal is greater than the nominal one by a factor of 3-4. On the contrary, the Ca intake is reduced by about a factor of 8 with respect to the starting composition, resulting in an actual content very similar to that reported in previous studies (Nagao et al, 2003(Nagao et al, , 2004Calore et al, 2013). Concerning the other elements, deviations from the ideal cationic ratios…”

“…Although a different growth strategy was also explored by adding either Sb or Te as a single heteroelement (Nagao, Yun, Nakane et al, 2005;Nagao et al, 2010), the crystal yield remained very limited in all cases. On the contrary, a very recent experiment has shown that the addition of limited amounts of Al 2 O 3 powder to the Te-and Ca-doped precursors remarkably increases the amount of grown Y-123 whiskers (Calore et al, 2013). Of course, the presence of so many different elements raises questions about possible contaminations of the HTSC crystals during the growth process and the corresponding decrease of their superconducting properties, especially due to substitution of the Y and Ba elements by Te and Ca.…”

Effect of Al and Ca co-doping, in the presence of Te, in superconducting YBCO whiskers growth

“…In our experiments, improving the work of Nagao et al (2003Nagao et al ( , 2004Nagao et al ( , 2005Nagao et al ( , 2010, we have shown that the addition of limited amounts of Al 2 O 3 powder to Cadoped precursors, in the presence of Te, remarkably increases the amount of grown Y-123 whiskers. Therefore, we synthesized Al-doped Y(Ca)Ba 2 Cu 3 O 7 À x whiskers via a solid-state reaction method (Calore et al, 2013).…”