Fully anisotropic superconducting transition in ion-irradiated YBa2Cu3O7-d with a tilted magnetic field

TL;DR

This study reveals a new type of fully anisotropic critical behavior during the vortex solid-to-liquid transition in ion-irradiated YBa2Cu3O7-d superconductors under tilted magnetic fields, characterized by direction-dependent resistivity scaling.

Contribution

It demonstrates the existence of a fully anisotropic critical point with distinct exponents in different spatial directions, expanding understanding of phase transitions in high-temperature superconductors.

Findings

Resistivities vanish at the transition with different powers in three directions.

Evidence for a new type of critical behavior with fully anisotropic exponents.

Transition behavior depends on the angle between magnetic field and defects.

Abstract

We consider the superconducting vortex solid-to-liquid transition in heavy ion-irradiated untwinned YBa2Cu3O7-d 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.