Microstructure of PtO2-doped melt-textured Y1Ba2Cu3O7-δ

✍ Scribed by D. Müller; M. Ullrich; K. Heinemann; H.C. Freyhardt

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 184 KB
• Volume: 235-240
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(94)91456-7

✦ Synopsis

Melt-textured YIBa2Cu3OT-6 was processed by the VGF(vertical gradient freeze)-method. The precursor had an excess of 25mo1% Y2BaCuO5 (211) and 1.8mo1% PtO2. jc of these samples is enhanced compared to melt-textured YIBa2Cu3OT-~ with excess 211 but without PtO2 doping. In order to understand this enhancement in j~, a detailed microstructural study was performed by transmission electron microscopy. The twin spacings in these samples are reduced to 50-100nm compared to twin spacings of 200-300nm in melt-textured Y1Ba2Cu3OT_~ without PtO2 doping. The PtO2 doping leads to a reduced size (< lpm) and an enhanced density (2× 101S/m 3) of the 211 particles. Most of the 211/123 interfaces are almost clean and free of crystal defects. Only a few of them were surrounded by defects like stacking faults. Therefore, we conclude that the the 123/211 interface is the dominant pinning center in the PtO2 samples. The Cu required for the stacking fault formation near the 211 particles originates from the 211 inclusions as confirmed by EDX.