中国物理B ›› 1993, Vol. 2 ›› Issue (12): 937-946.doi: 10.1088/1004-423X/2/12/008
• • 上一篇
曹国辉1, 赵忠贤2, 刘鹏2, 张进龙2, 司卫东2, 黄以能3, 王业宁3, 陈沙鸥3, 周海龙3, 张清明3, 沈惠敏3, 杨震3
HUANG YI-NENG (黄以能)a, WANG YE-NING (王业宁)a, CHEN SHA-OU (陈沙鸥)a, ZHOU HAI-LONG (周海龙)a, ZHANG QING-MING (张清明)a, SHEN HUI-MIN (沈惠敏)a, YANG ZHEN (杨震)a, ZHAO ZHONG-XIAN (赵忠贤)b, LIU PENG (刘鹏)b, ZHANG JIN-LONG (张进龙)b, SI WEI-DONG (司卫东)b, CAO GUO-HUI (曹国辉)c
摘要: For both BiSrCaCuO and TlBaCaCuO samples, internal frictions (Q-1) in the kHz range reveal a plateau (Q-1p) above Tc and a rapid drop below Tc with the turning points located just at Tc for various samples with different Tc. This anomaly cannot be observed in non-superconducting samples. The ultrasonic attenuation (α) in TlBaCaCuO displays similar results to the internal friction. Moreover, it is discovered that the Q-1p is nearly proportional to the carrier density for Y(Pr)BaCuO and Gd(Pr)BaCuO with different Pr contents. These results show that the drop of Q-1 and a below Tc is closely related to superconducting condensation. The Q-1p and αp can be explained using coupling-model of carriers with local dynamic distortion because high Tc superconductors are strong-correlation systems. Furthermore, by taking account of the smearing of superconducting gap structure resulting from the recombination of quasi-particles and by modifying the BCS relative jump rate as S(E, E', Γ) = Re{1-Δ2/[(E-iΓ)(E'-iΓ)]}, the calculated results of internal friction and ultrasonic attenuation below Tc are in good agreement with the experimental data. The superconducting gap Δ and the damping rate Γ for both BiSrCaCuO and TlBaCaCuO have also been obtained, they are in accordance with those got by tunneling spectrum and NMR methods, etc.
中图分类号: (Mechanical and acoustical properties, elasticity, and ultrasonic Attenuation)