ELASTIC BEHAVIOR OF A Y-BA-CU-O SAMPLE PREPARED BY THE MPMG METHOD

Ultrasonic velocity measurements have been undertaken by the pulse tra nsmission technique using Y-Ba-Cu-O samples prepared by the melt-powde r-melt-growth (MPMG) process over a temperature range of 80-300 K. It has been observed that the sample exhibits a very high value of Young' s and rigidity moduli, thereby indicating that the material is an exce llent one from the point of view of its mechanical strength. Further, the Young's modulus apart from exhibiting a hump at around 120 K, is f ound to increase continuously with decreasing temperature. In the supe rconducting phase, however, the modulus is found to remain almost cons tant. It has been concluded that the observed elastic behavior, to a l arge extent, is analogous to that of normal oxide materials. In order to understand how far the experimentally observed behavior deviates at 120 K, the elastic moduli of the sample were also estimated theoretic ally and compared with the empirical values.