Multi-Stable Static Resistive States of High- $T_{\rm c}$ Superconductors With Temperature-Decreasing Power Exponent of Their Voltage-Current Characteristic

The possible resistive states of high-T_c superconductor without the stabilizing matrix are investigated in the static approximation considering the temperature decreasing dependence of the power exponent (n-value) of its voltage-current characteristics. The analysis is performed for the superconductor placed in a constant external magnetic field at different operating temperature and cooling conditions. It is shown that the stable static resistive states may be observed in the high values of electric field and overheating. Multi-stable resistive modes may occur because of non-trivial changes in the differential resistivity of the superconductor. In the formation of these modes, the primary role plays the interconnected decrease of the critical current density and n-value with increasing temperature of a superconductor. The existence of multi-stable resistive states must be taken into account when the stable regimes of high-T_c superconductors are analysed or the processes occurring in the high-T_c superconducting magnets during their transition into the normal state are investigated.