Eur. Phys. J. B 29, 369-375 (2002)
https://doi.org/10.1140/epjb/e2002-00320-9

High field transport properties of La_2-xSr_xCuO₄ epitaxial thin films

Laboratorium voor Vaste-Stoffysica en Magnetisme, Katholieke Universiteit Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium

Corresponding author: ^a liesbet.weckhuysen@fys.kuleuven.ac.be

Received: 4 January 2002
Revised: 7 May 2002
Published online: 14 October 2002

Abstract

We have studied the temperature dependent resistivity of La_2-xSr_xCuO₄ epitaxial thin films in the doping range in pulsed magnetic fields up to 50 T. The zero-field resistivity of these samples in the pseudogap regime, can be scaled onto one single universal curve in a broad temperature range by using a linear transformation of both temperature and resistivity. The high field data reveal a metal to insulator transition (MIT) at low temperatures, well into the overdoped regime. For samples having , with k_F the Fermi wave vector and l the mean free path, this low temperature insulating behavior of the resistivity is described by the variable range hopping conductivity (VRH). For samples with , the divergence follows or a power law, depending upon the Sr-content. We further found that the residual conductivity at the minimum in , appearing due to the MIT, follows a linear behavior with respect to the Sr-content. It is argued that the unusual MIT in compounds with , is most probably associated with the pseudogap and the behavior of charge stripes at low temperatures.