# Investigations of the Structure and Superconducting Properties of the pr(Ca)-Ba(La)-Cu-O system: $Pr_{1-x}Ca_xBa_2Cu_3O_{7-\delta}$, $PrBa_{2-x}La_xCu_3O_{7-\delta}$ and $Pr_{1-x}Ca_xBaLaCu_3O_{7-\delta}$

Nagarajan, R and Pavate, Vikram and Rao, CNR (1992) Investigations of the Structure and Superconducting Properties of the pr(Ca)-Ba(La)-Cu-O system: $Pr_{1-x}Ca_xBa_2Cu_3O_{7-\delta}$, $PrBa_{2-x}La_xCu_3O_{7-\delta}$ and $Pr_{1-x}Ca_xBaLaCu_3O_{7-\delta}$. In: Solid State Communications, 84 (1-2). pp. 183-186.

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## Abstract

Prompted by a literature report that thin films of $Pr_{0.5}Ca_{0.5}Ba_2Cu_3O_{7-\delta}$ are superconducting, the structure and bulk properties orthorhombic $Pr_{1-x}Ca_xBa_2 Cu_3O_{7-\delta}$ and tetragonal $PrBa_{2-x}La_xCU_30_{7-\delta}$ have been investigated, these systems do not show superconductivity.Tetragonal $Pr_{1-x}Ca_xBaLaCu_30_{7-\delta}$, on the other hand, shows superconductivity when x=1.0 and 0.8 with onset $T_c$'s of 66 K and 46 K respectively; compositions with x < 0.6 are semiconducting. Since the hole concentration in $PrBa_2Cu_30_{6.9}$, $PrBaLaCu_30_{7.42}$ and $CaBaLaCu_30_{6.9}$ are comparable, the absence of superconductivity in the first two cuprates is likely to be due to the location of the 4f level of $Pr^{3+}$ in the vicinity of the Cu-O band.

Item Type: Journal Article Copyright of this article belongs to Elsevier Science Ltd. Division of Chemical Sciences > Solid State & Structural Chemistry Unit 20 Dec 2007 19 Sep 2010 04:32 http://eprints.iisc.ernet.in/id/eprint/8777