Transport and magnetic properties of La_(1-x)Ca_xMnO_3-films (0.1<x<0.9)

TL;DR

This study investigates the transport and magnetic properties of La_(1-x)Ca_xMnO_3 thin films with varying doping levels, revealing different conduction mechanisms and magnetic behaviors depending on doping and temperature.

Contribution

It provides systematic experimental data on how doping affects the magnetic and transport properties of La_(1-x)Ca_xMnO_3 films, including epitaxial growth and conduction mechanisms.

Findings

Epitaxial growth confirmed by X-ray diffraction.

Polaronic transport observed above Curie temperature in metallic samples.

Variable range hopping transport in low-doped insulating samples.

Abstract

By laser ablation we prepared thin films of the colossal magnetoresistive compound La_(1-x)Ca_xMnO_3 with doping levels 0.1<x<0.9 on MgO substrates. X-ray diffraction revealed epitaxial growth and a systematic decrease of the lattice constants with doping. The variation of the transport and magnetic properties in this doping series was investigated by SQUID magnetization and electrical transport measurements. For the nonmetallic samples resistances up to 10^13 Ohm have been measured with an electrometer setup. While the transport data indicate polaronic transport for the metallic samples above the Curie temperature the low doped ferromagnetic insulating samples show a variable range hopping like transport at low temperature.