Hall effect and magnetoresistance in the normal state of the superconductor LaO$_{0.9}$F$_{0.1-x}$FeAs

TL;DR

This study investigates the normal state electrical transport properties of LaO$_{0.9}$F$_{0.1-x}$FeAs superconductor, revealing electron-dominated conduction, anomalous temperature behavior, and deviations from classical magnetoresistance laws.

Contribution

First detailed measurement of Hall effect and magnetoresistance in LaO$_{0.9}$F$_{0.1-x}$FeAs, highlighting anomalous properties and potential multi-band effects.

Findings

Negative Hall coefficient indicating electron-like carriers

Charge carrier density around 9.8E20 cm^-3 at 100K

Anomalous behavior near 240K in transport properties

Abstract

By using a two-step method, we successfully synthesized the iron based new superconductor LaO$_{0.9}$F$_{0.1-x}$FeAs. The Hall effect and magnetoresistance were measured in wide temperature region. A negative Hall coefficient R_H has been found implying a dominant conduction by electron-like charge carriers in this material. The charge carrier density determined at 100K is about 9.8E20 cm-3, which is close to the cuprate superconductors. It is further found that the magnetoresistance does not follow the Kohler's law. Meanwhile, the Hall coefficient, the resistivity at 0T, and magnetoresistance all have an anomalous property at about 240K, which may be induced by the multi-band effect or by some exotic scattering mechanism.