Angular, field and temperature dependence of critial currents of superconducting nickelates thin films

We present linear and non-linear transport results on La_0.8Ca_0.2NiO₂ thin films as a function of temperature (T), magnetic field strength (H) and orientation (q ). We observe that the vortex solid-liquid transition, marked by the onset of the critical current, is well below that of the typical loss of sensitivity of linear transport.

We analyze the temperature and field dependences, identifying different regimes characterized by a collective behavior with the critical current density (J_c ) proportional to H ^-a, followed by a faster decrease as function of field. This is correlated with a change in the pinning nature observed as a different n vs J relation, with n defined as V α I ⁿ.

The combination of field orientation and strength give further insight on the nature of pinning regimes and dimensional changes present in the superconducting nickelate films.