Synthesis of cuprate superconductors

Abstract

There has been unprecedented activity pertaining to t h e synthesis and characterization of superconducting cuprates in the last few years. A variety of synthetic strategies has been employed to prepare pure monophasic cuprates of different families with good superconducting properties. Besides the traditional ceramic method, other methods such as coprecipitation and precursor methods, the sol-gel method. the alkali flux method and the combustion method have been employed for the synthesis of cuprates. Depending on t h e requirements, varying conditions such as high oxygen or hydrostatic pressure and low oxygen fugacity are employed in the synthesis. In this review, we discuss the synthesis of the various types of cuprate superconductom and point out the advantages and disadvantages of the different methods. We have provided the necessaw preparative details, presenting the crucial information in tabular form wherever necessary. * Contribution No 874 from the Solid Stale and Structural Chemistry Unit. 45 30 4c-110 ~ Ceramic*, sol-gel, combustion, coprecipitation Ceramic (high 0, pressure)' Ceramic (high 0, pressure)* alkali-flux, hypobromite* Ceramic (annealing in OJ*, sol-gel', coprecipitation*, Ceramic (high 0, pressure), ceramic (with Na,O,)* Ceramic (air-quench)* sol-gel*, combustion, Ceramic*, sol-gel, melt route Ceramic (sealed Ag/Au tube)* Ceramic (sealed Ag/Au tube)* Ceramic (sealed Ag/Au tube)* Ceramic (sealed Ag/Au tube)* Ceramic (sealed Ag/Au tube)* Ceramic (sealed Ag/Au tube)* Ceramic (low 0, partial pressure),* combustion sol-gel*, coprecipitation* melt (glass) route* sol-gel' (low 0, partial pressure) Ceramic (flowing O,)* Ceramic (low 0, partial pressure): Coprecipitation (low 0, partial pressure)* Ceramic (high pressures)* , -" " -4CL110 Ceramic (high pressures)* Recommended methods are indicated bv asterisks. ~~~~ ~~ ~~~~~~ 'Other rare-earth compounds of this type are also prepared by similar methods. Oxygen annealing is done below the orthorhombicAetragona1 transition.

Applications and Preparation Methods of Copper Chromite Catalysts: A Review

“…In this method catalysts are obtained [291,334] by mixing of support (γ-Al2O3) with an aqueous solution of chromium anhydride and copper nitrate in required proportion. The amount of solution taken is sufficient for incipient wetness to be observed.…”

Room Temperature Superconductivity

“…The most relevant doping procedures used for the synthesis of cuprate superconductors have been described in a review article (Rao et al, 1993). Historically, the first synthesis of a high-T c oxide superconductor was the copper oxide Ba x La 2-x CuO 4 (Bednorz & Muller, 1986).…”

A Model to Study Microscopic Mechanisms in High-Tc Superconductors

“…The most relevant doping procedures used for the synthesis of cuprate superconductors have been described in a review article (Rao et al, 1993). The first high-Tc oxide superconductor was the copper oxide Ba x La 2-x CuO 4 (Bednorz & Muller, 1986).…”