Structural properties and magnetoresistance of La$_{1.952}$Sr$_{0.048}$CuO$_4$ thin films

TL;DR

This study investigates how compressive strain affects the structure and electrical transport in underdoped La$_{1.952}$Sr$_{0.048}$CuO$_4$ thin films, revealing inhomogeneous superconductivity and a magnetic-field-driven superconductor-insulator transition.

Contribution

It provides new insights into the effects of epitaxial strain on the structural and superconducting properties of underdoped cuprate thin films.

Findings

Superconductivity onset at 26 K in thin films.

Residual resistance indicates inhomogeneous superconductivity.

Superconductor-insulator transition occurs at about 32 T.

Abstract

The evolution of the structural and transport properties of underdoped La$_{1.952}$Sr$_{0.048}$CuO$_4$ thin films under compressive epitaxial strain has been studied. The films of different thicknesses $d$ (from 26 nm to 120 nm) were deposited using an insulating target. The onset of superconductivity in the films is observed at temperatures as high as 26 K, while small residual resistance persists at low temperatures, indicating that superconductivity is inhomogeneous. The resistance measured under perpendicular magnetic field saturates below about 0.65 K, suggesting a possible existence of nonconventional metallic state. The magnetic-field-tuned superconductor-insulator transition is observed at magnetic field of about 32 T.