Preparation of electron-doped La(2-x)CexCuO4 thin films with various Ce doping by dc magnetron sputtering

TL;DR

This study synthesizes and analyzes La(2-x)CexCuO4 thin films with varying Ce doping levels, examining how fabrication conditions affect film quality and revealing a superconducting dome with optimal doping at x=0.105.

Contribution

It provides a systematic investigation of fabrication parameters on film quality and maps the superconducting phase diagram for electron-doped La(2-x)CexCuO4 thin films.

Findings

Superconducting dome peaks at x=0.105 with Tc0=26.5 K.

Film quality less sensitive to deposition temperature in overdoped region.

Fermi surface rearrangement suggested around x=0.15.

Abstract

A series of c-axis oriented electron-doped high-Tc superconducting La(2-x)CexCuO4 thin films, from heavily underdoped x=0.06 to heavily overdoped x=0.19, have been synthesized by dc magnetron sputtering technique on (100) SrTiO3 substrates. The influence of various fabrication conditions, such as the deposition temperature and the deposition rate, etc., on the quality of the thin films has been scrutinized. We find that the quality of the films is less sensitive to the deposition temperature in the overdoped region than that in the underdoped region. In the phase diagram of Tc(x), the superconducting dome indicates that the optimally doping level is at the point x=0.105 with the transition temperature Tc0 = 26.5 K. Further more, both the disappearance of the upturn in the $\rho_{xx}$(T) curve at low temperature under H=10 T and the positive differential Hall coefficient, $R_H'=d \rho_{xy}/dH$, are observed around x = 0.15, implying a possible rearrangement of Fermi surface at this doping level.