Implications of magnetic-hysteresis-loop scaling in high-temperature superconductors

Abstract

We show how to incorporate the commonly observed scaling behavior of magnetic hysteresis loops M(H) in (R)Ba2Cu307 z (R =rare earth) crystals into a systematic and straightforward analytical procedure that yields the key parameters associated with the vortex dynamics. If the effective barrier height for vortex motion is written in terms of a scale energy Uo(B, T) and a scale current density Jo(B, T), both the field and temperature dependences of these quantities can be found directly from the experimental data, without any deconvolution. The procedure is illustrated with the data on one specific sample of TmBazCu307 z. Over a substantial region of the B-T plane, Jo(B, T) is found to be~B and essentially temperature independent; Uo(B, T) is approximately~1/B and decreases steadily as T, is approached. The competition between the field dependences of Jo(B,T) and Uo(B, T) gives rise to the ubiquitous "fishtail" in the magnetization loops.

Effect of mesoscopic inhomogeneities on the critical current of bulk melt-textured YBCO

“…Perkins et al [24][25], Tirsa et al [26], based on the theory of collective vortex pinning, developed a method for generalization of experimental results for J c (B,T) for a considerable number of different Re(123) using only two parameters which govern the vortex pinning condition. But the physical essence of these parameters, their dependence on the real structure of RE(123) are not clear yet.…”

Effects of heavy-ion irradiation on FeSe

“…As has been demonstrated in several superconductors, the MHLs at different temperatures can be well scaled onto one curve by choosing appropriate reducing parameters M * and H * , if one single pinning mechanism is dominant [43][44][45][46]. The scaled MHLs at several temperatures for the pristine and Uranium irradiated FeSe with typical doses of B φ = 2 T, and 8 T are shown in Figs.…”

Modelling of Critical Current Density of Sintered Ag Added Bulk MgB2

“…Up to now, several models have been proposed based on thermodynamic and some phenomenological considerations. For bulk high T c superconductors with an intensive thermally activated flux motion Perkins et al [28,29] and Jirsa et al proposed a model enabling to fit the secondary peak on the critical current density as a function of magnetic field [30]. It worked well for NEG-123 and Gd-123 bulks and for Eu-123 thick films [14].…”