Magnetothermal instabilities in type II superconductors: The influence of magnetic irreversibility

Abstract

Complete magnetization and magnetostriction loops for type II superconductors were calculated in terms of the following pinned critical state models which incorporate the flux jump instability criterion: the Kim–Anderson model, the exponential model, the linear model, and the model with peak effect. These results were used for constructing magnetic field–temperature (H–T) diagrams of instability of these critical state models. Magnetothermal instabilities of superconductors with peak effect were investigated experimentally and theoretically. Regions in the H–T diagram where flux jumps occur were built and compared with experimental M(H) hysteresis loops. We have explained the phenomenon of “island” jumps. The influence of flux trapping on the flux jump regions of magnetic fields was studied.

Magnetization jumps in a lead-porous glass composite: Experiment and simulation

“…4. This scheme was further developed in later works 6,15 where more intricate critical current profiles were used for particular superconductors.…”

“…@Hðx; H e ; TÞ @H e aðxÞ; (15) which leads to the following relationship for the instability condition…”

“…For the factor gðHÞ which defines the field dependence of the critical current one generally considers various functions. 4,6,14,15 The most common of them are the Kim-Anderson dependence…”

“…6 and 14 and references therein), which have low heat capacity and possibility to transport high enough J c . For YBaCuO, 4 Nb-plate 15 and MgB 2 , 6,14 numerical calculations showed the validity of the adiabatic limit for treating the magnetization jumps within a large range of the field sweep rate. More general numerical approach which takes into account the kinetics of heat exchange with the bath was suggested in Ref.…”

Model calculations for the high-field peak of the fish-tail effect in the magnetostriction of type-II superconductors

“…As a result, it might be expected that certain characteristic features of magnetization also have parallel features in magnetostriction [33,14]. Therefore, to treat the anomalities observed in magnetostriction experiments, a way similar to that for the magnetization [34,35] can be pursued.…”