Elastic properties of superconducting Pb(1+x)/2Cu(1−x)/2(Sr1−yCay)2(Y1−xCax)Cu2O7+δ

✍ Scribed by Jun Sugiyama; Kazuyuki Isawa; H. Yamauchi

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 338 KB
• Volume: 242
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(94)02408-1

✦ Synopsis

Using a vibrating reed technique, internal friction (Q -1 ) and Young's-modulus sound velocity (VE) were measured for polycrystalline samples of two types of superconducting Pbo.75Cuo.2s(Sro.9Cao.l )2(Yo.5Cao.5)Cu207+6 (Tc= 58 and 48 K) and insulating Pbo.sCuo.sSr2YCu207 in the temperature range between 30 and 300 K. For each of the samples, a broad peak was observed at 180 K in the Q-1 vs. T curve. For superconducting samples, VE increased monotonically with lowering temperature. Moreover, there appeared to be a distinct change in slope of VE(dV~/dT) around 230 K. For an insulating sample, as temperature lowered, VE increased monotonically without any obvious change in dVE/dT. Furthermore, it was found that the temperature dependence of the magnitude of slope ( -d V~/dT) was akin to that of Q-~ for each sample. These behaviors were thought to be attributable to collective displacements of oxygen atoms and/or Pb and Cu atoms in the (Pb,Cu)-O plane.