Critical current density of four-CuO2-layer TlBa2Ca3Cu4O11+δ single crystals

A key requirement for technological application is to have superconductors with high critical current density at practical operating temperatures and magnetic fields. The critical current density is strongly related to underlying properties of high Tc superconductors, such as laying, anisotropy and other intrinsic material structures. The thallium-based superconductors attracted much attention at an early stage mainly due to their high superconducting transitions. Our single crystal studies on TlBa2Ca3Cu4O11+δ show that these materials appear to be a better choice for achieving higher critical current density because of a stronger interlayer coupling between superconducting layers. (author)