Fully anisotropic superconducting transition in ion-irradiated Y Ba2 Cu3 O7-δ with a tilted magnetic field

We consider the superconducting vortex solid-to-liquid transition in heavy ion-irradiated untwinned Y Ba2 Cu3 O7-δ single crystals in the case where the magnetic field direction does not coincide with that of the irradiation-induced linear columnar defects. For a certain range of angles, the resistivities measured in three orthogonal spatial directions vanish at the transition as three clearly different powers of reduced temperature. At previously known second-order phase transitions, scaling of physical quantities has either been isotropic or anisotropic in one direction. Thus, our findings yield evidence for a new type of critical behavior with fully anisotropic critical exponents.