ANISOTROPIC RESCALING OF A SPLAYED PINNING LANDSCAPE IN HG CUPRATES -STRONG VORTEX PINNING AND RECOVERY OF VARIABLE-RANGE-HOPPING

Strong vortex pinning by fission-induced uniformly splayed columnar tr acks in anisotropic mercury cuprates is demonstrated to result from (r e)scaling of the pinning landscape by a large superconducting anisotro py. The effective ''narrowing'' of the splay distribution restores var iable range vortex hopping (VRH) motion expected for nearly parallel p ins. VRH emerges as a distinctive peak in the vortex creep rate (simil ar to 12% at low fields at T/T-c similar to 0.5) of the most anisotrop ic HgBa2Ca2Cu3O8+delta, a peak well described by a glassy dynamics wit h the characteristic exponent mu similar to 1/3. [S0031-9007(98)07526- 7].