Critical currents and magnetization of a (Tl_0.5Pb_0.5)(Sr_0.85Ba_0.15)₂Ca₂Cu₃O_zfilm on silver substrate

Abstract

A thin film of a (Tl 0.5 Pb 0.5 )(Sr 0.85 Ba 0.15 ) 2 Ca 2 Cu 3 O z superconductor was prepared on highly polished silver substrates. Its superconducting transition temperature (T c,50% ) is 114.7 ± 0.3 K and the critical current density is 11.4 × 10 3 A cm −2 at 77 K in the self-field. The transport critical currents densities were measured as a function of temperature for several applied magnetic fields. The magnetization versus the dc applied magnetic field and temperature were also measured and the critical current densities were calculated. The temperature dependence of the critical currents obeys the Ginzburg-Landau power-law. Reasons for this behaviour were discussed taking into account the pinning force and anisotropy of the critical currents associated with the c-axis grain orientation of the film. The magnetization as a function of the angle between the applied magnetic field and the a-b plane showed a periodic dependence due to changes of the demagnetizing field.

Study of Resistive Superconducting Transition of Thallium Based Superconductors

“…On the other hand, higher than 2/3 values of m suggest the pinning force is weak and the vortex structure is like in HTS. These results are consistent with the temperature dependence of the critical currents and of the irreversibility elds [15,16]. The interesting features of the broadening of the resistive transition may be observed in the (Tl 0.5 Pb 0.5 )Sr 2 (Ca 1−x Gd x )Cu 2 O z superconductors (see Fig.…”

Resistance and AC Susceptibility of YBCO 1:2:3 Films on Silver Substrates

“…where T c is the critical temperature that depends on the applied magnetic eld and J c0 is the critical current at 0 K. Originally, the exponent n was determined to be 1.5 [10] but it may vary within a wide range [11]. If the exponent n is greater than unity there is a strong pinning and the vortex glass structure exists.…”

Magnetization, Susceptibility and Critical Currents of (Tl2-xRex)Ba2CaCu2OyThin Films

“…(2) are very large in comparison to other thalliumbased superconductors which usually are not larger than two [3,4,24]. This means that the vortices are being arranged in the glassy-like structure with the strong pinning force [22]. As a consequence the large values of the critical currents were found out for the investigated thallium-rhenium thin lms (see Table II).…”

“…T c0 depends on the applied magnetic eld. J c0 is the critical current extrapolated to 0 K. Originally, the exponent n was determined to be 1.5 but it may vary within a wide range [21,22]. If the exponent n is greater than unity then the strong pinning and a vortex glass structure exist.…”