Wang Yayu, Li Lu, Naughton M J, Gu G D, Uchida S, Ong N P
Department of Physics, Princeton University, New Jersey 08544, USA.
Phys Rev Lett. 2005 Dec 9;95(24):247002. doi: 10.1103/PhysRevLett.95.247002. Epub 2005 Dec 5.
In hole-doped cuprates, Nernst experiments imply that the superconducting state is destroyed by spontaneous creation of vortices which destroy phase coherence. Using torque magnetometry on Bi2Sr2CaCu2O(8+delta), we uncover a field-enhanced diamagnetic signal M above the transition temperature Tc that increases with applied field to 32 Tesla and scales just like the Nernst signal. The magnetization results above Tc distinguish M from conventional amplitude fluctuations and strongly support the vortex scenario for the loss of phase coherence at Tc.
在空穴掺杂的铜酸盐中，能斯特实验表明，超导态会因自发产生破坏相位相干性的涡旋而被破坏。通过对Bi2Sr2CaCu2O(8+δ)进行转矩磁强计测量，我们发现在转变温度Tc以上存在一个场增强的抗磁信号M，该信号随外加磁场增加至32特斯拉，并且其标度与能斯特信号完全相同。高于Tc的磁化结果将M与传统的幅度涨落区分开来，并有力地支持了在Tc时相位相干性丧失的涡旋图景。
