Flux Dynamics in Ln(Ba_2-xPr_x)Cu₃O_7+δ (Ln=Tm, Lu)

Abstract

Single-phase Tm(Ba2-xPrx)Cu3O7+δ and Lu(Ba2-xPrx)Cu3O7+δ compounds with Pr content 0.0≤x≤1.0 have been prepared by solid-state reaction technique. The oxygen content of our samples is more than 7. X-ray diffraction (XRD) patterns demonstrate an orthorhombic to tetragonal transition with an increase in Pr content in both systems. For each system, a solubility limit exists for substitution of Pr at the Ba site. The intergrain region investigated by the thermally activated flux creep (TAFC) and Ambegaokar–Halperin (AH) models, show that the pinning energy decreases with increasing Pr content; it also decreases in each sample with increasing magnetic field as a power-law relation. The temperature and magnetic field dependences of pinning energy in Lu(BaPr)-123 are less than in Tm(BaPr)-123. The intergrain Jc obtained from I–V curves decreases with increasing Pr content and decreases with increasing magnetic field as a power-law relation. Also, the intragrain Jc obtained from the M–H curves, decreases with increasing magnetic field. In both Tm- and Lu-based samples, intragrain Jc is approximately three orders of magnitude larger than intergrain Jc.

Structural aspects and the conduction mechanism of Ln(Ba2–xPrx)Cu3O7+δ (Ln = Tm, Lu)

“…This could be due to the stronger effect of Pr on the Lu-based compound than on the Tm-based compound, which in turn, could be affected by the difference in their magnetic properties. This point is investigated in detail and reported elsewhere [47].…”

Substitution of Nd at Ba site in Gd123

“…Á˯ is the normalized barrier height for thermally activated phase slip (TAPS), I 0 is the modified Bessel function, and ρ n is the average normal-state resistivity of the junction. The reported values for q are 1.53-2.8 [23]. Figure 6 shows the experimental magnetoresistance data and the fitted curves to the AH model for Gd(Ba 1.9 Nd 0.1 )Cu 3 O 7.01 .…”