Elastic behavior of melt-powder-melt-growth processed YBa2Cu3O7-delta

The ultrasonic velocity measurements of a Y-Ba-Cu-O material, prepared by M elt-Powder-Melt-Growth process (MPMG) with Nd-123 as a seed material, known as MPMG-II material, have been undertaken by the pulse transmission techni que over a temperature range 80-300 K. It has been observed that the MPMG-I I material, in contrast to Y-123 material also prepared by the Melt-Powder- Melt-Growth method without using any seed material, designated as MPMG-II, exhibits a very high Young's and rigidity modului, which are comparable wit h those of single crystalline ones. Further, it has also been observed that the longitudinal velocity is found to increase continuously with decreasin g temperature right up to liquid nitrogen temperature, i.e. 80 K, without s howing any anomaly, whatsoever, thereby indicating that the behavior resemb les a normal solid having normal behavior. From these two observations, it has been speculated that MPMG-II material may be free from all types of lat tice instabilities and that it may be approaching mechanically a single cry stalline Y-123 material.