EFFECT OF NANO-SIZED OXALATE PRECURSOR ON THE FORMATION OF GdBa2Cu3O7-δ PHASE VIA COPRECIPITATION METHOD.

The formation of GdBa₂Cu₃O_7-δ(Gd123) from metal oxalate precursor with average grain size less than 40 nm using the coprecipitation method is reported. The coprecipitated powders were heated at 900°C for 12 hours, pelletized and then sintered at 920°C for 15, 20 and 25 hours, respectively. All samples showed a dominant Gd123 phase with the orthorhombic structure. The amount of impurity phase Gd₂BaCuO₅(Gd211) can be controlled by varying the sintering time. This work shows that nano-sized oxalate powders produced via coprecipitation method can be an effective technique to synthesize high quality GdBa₂Cu₃O_7-δ samples where the amount of (Gd211) can be controlled by varying the sintering duration. The percentage of Gd211 impurity decreased with increase in sintering time. This result is useful in utilizing the Gd211 phase as pinning center in enhancing the transport properties. [ABSTRACT FROM AUTHOR]