High critical-current densities in (Tl0.5Pb0.5)Sr2Ca2Cu3O9 with T c up to 115 K

Abstract

A high critical-current density was observed in the material (Tl0.5Pb0.5)Sr2Ca2Cu3O9. Based on magnetic-hysteresis measurements, this single (insulating) Tl-O layer material has a Jc value of 1.24×105 A/cm2 when measured at a temperature of 77 K and a field of 1 T. This value of Jc is comparable to that measured here for YBa2Cu3O7 (1.04×105 A/cm2), having single-conducting Cu-O chains, but considerably greater than the value for the material Tl2Ba2Ca2Cu3O10 with double (insulating) Tl-O layers in which no hysteresis was observed under these same conditions. Our results from specific heat measurements indicate that the (Tl0.5Pb0.5)Sr2Ca2Cu3O9 compound has a three-dimensional character due to the enhancement of the superconducting coupling along the c axis between the Cu-O planes and thus results in an increase in Jc compared to the two-dimensional Bi- and Tl-2212 and 2223 [e.g., (Bi or Tl)2(Sr or Ba)2CaCu2O8 and (Bi or Tl)2(Sr or Ba)2Ca2Cu3O10, respectively] compounds. We believe that the high Jc is associated with an increase in the irreversibility field, rather than an increase in pinning centers.

Unprecedented high irreversibility line in the nontoxic cuprate superconductor (Cu,C)Ba 2 Ca 3 Cu 4 O 11+δ

“…This phase line actually separates the phase diagram into zero and finite resistive dissipation. In the cuprate family, some compounds of the Bi-based ( 1 ), Hg-based ( 2 ), and Tl-based ( 3 ) systems show superconducting transition temperatures beyond 100 K. Among all these materials, it was reported that the (Tl 0.5 Pb 0.5 )Sr 2 Ca 2 Cu 3 O 9 [(Tl,Pb)-1223] ( 4 , 5 ) exhibits a rather high irreversibility line with an irreversibility field of nearly 10 T at the liquid nitrogen boiling temperature (~77 K), which is thought to be promising for applications. However, for Hg- and Tl-based systems, the toxic elements Hg and Tl strongly limit the high-power applications of these materials.…”

A Search for a Low Anisotropic Superconductor

“…The Tl-1223 superconductors have been found to have higher J c as compared to Tl-2212 and Tl-2223 compounds [47,49,50]. The Tl-1223 superconductors are very useful in electronic devices fabrication because the critical currents in these compounds decreases slowly as compared to double Tl-O layer compounds in the presence of external magnetic fields [47,55]. In Figure 12, a comparison of the magnetic field dependence of J c (77K) of Tl-1223 and Tl-2212 is shown.…”

“…These superconducting compounds are more promising because of their lower anisotropy, higher T c (0), higher critical current densities and irreversibility field H irr as compared to their counterparts in double Tl-O layer superconductors family [47][48][49][50][51][52][53][54][55]. The TlSr 2 CaCu 2 O 7 (Tl-1212) is the parent compound in single Tl-O layer superconductors showing no signs of superconductivity down to liquid helium temperature because it grows in the over-doped state [56].…”

Excess conductivity analysis and infrared absorption spectroscopy of Mg-doped TlBa2Ca2Cu3O10-δ superconductor

“…The single Tl-O layer compounds have primitive tetragonal structure. The higher superconducting properties of single layer thallium-based compounds make them preferable over double layer thallium-based compounds [9][10][11][12][13][14].…”

“…These compounds can be generally represented by Tl-22(n − 1)n, where "n" represents the number of CuO 2 planes. On the other hand, the monolayer Tl-based system includes TlBa 2 [6][7][8][9][10][11][12][13][14]. The single Tl-O layer compounds have primitive tetragonal structure.…”