Josephson-Vortex-Glass Transition in Strong Fields

A vortex-glass transition due to point disorder in layered superconductors is studied for the case with an applied field {\it parallel} to the layers. Our calculation of tilt responses indicates that, irrespective of the magnitude of the field, the resulting glass phase, Josephson-vortex-glass (JG), should have a transverse Meissner effect, as in a planar splayed glass phase, only for a tilt perpendicular to the layers. Further, focusing on the high field (and/or high anisotropy) region $B \sqrt{\Gamma} > \phi_0/d^2$, where $\Gamma$ is the mass anisotropy in the Lawrence-Doniach model, the JG transition line $T_{JG}(B)$ is shown to have a similar form to a $B$-$T$ line following from the {\it disorder-free} Lindemann criterion and to decrease with increasing $B \sqrt{\Gamma}$, in marked contrast to the disorder-free melting line {\it insensitive to} $B \sqrt{\Gamma}$ in such the high field region. This $T_{JG}(B)$ line seems to have been recently observed in a.c. susceptibility and in-plane resistivity measurements in BSCCO and qualitatively explains a field dependence at lower temperatures of previous BSCCO resistivity data showing the so-called in-plane Lorentz force-free behavior.