High-magnetic-field transport properties of ${\mathrm{Bi}}_2$${\mathrm{Sr}}_2$${\mathrm{CaCu}}_2$${\mathrm{O}}_8$ single crystals

We have measured the high-magnetic-field dependences (up to 18 T) of the in-plane and out-of-plane transport properties of ${\mathrm{Bi}}_2$ ${\mathrm{Sr}}_2$ ${\mathrm{CaCu}}_2$ ${\mathrm{O}}_8$ (Bi-2:2:1:2) single crystals. From I-V curves of c-axis transport we extract the magnetic field and temperature dependences of the interlayer critical current and define a decoupling line ${\mathit{H}}_{\mathit{D}}$(T) above which ${\mathit{J}}_{\mathit{c},}$c vanishes. The temperature dependence of ${\mathit{J}}_{\mathit{c},}$c supports a first-order decoupling transition. The decoupling line lies close to the irreversibility line in the field interval 0.5–5 T. The field dependence of the in-plane vortex activation energy is ∼${\mathit{B}}^{\mathrm{-}0.5\pm 0.1}$.