History dependent magnetoresistance in lightly doped La_{2-x}Sr_{x}CuO_{4} thin films

TL;DR

This study investigates the in-plane magnetoresistance in lightly doped La_{2-x}Sr_{x}CuO_{4} thin films, revealing glassy behavior and history dependence at low temperatures, indicative of hole glassiness in the insulating state.

Contribution

It demonstrates that positive, history-dependent magnetoresistance is a robust feature of the insulating state in lightly doped La_{2-x}Sr_{x}CuO_{4} thin films, highlighting glassy hole dynamics.

Findings

Positive MR appears below 4 K in insulating films.

Magnetoresistance shows glassy features like history dependence.

Behavior is consistent across different magnetic field orientations.

Abstract

The in-plane magnetoresistance (MR) in atomically smooth La_{2-x}Sr_{x}CuO_{4} thin films grown by molecular-beam-epitaxy was measured in magnetic fields B up to 9 T over a wide range of temperatures T. The films, with x=0.03 and x=0.05, are insulating, and the positive MR emerges at T<4 K. The positive MR exhibits glassy features, including history dependence and memory, for all orientations of B. The results show that this behavior, which reflects the onset of glassiness in the dynamics of doped holes, is a robust feature of the insulating state.