Upper critical field, Hall effect and magnetoresistance in the iron-based layered superconductor LaFeAsO_{0.9}F_{0.1-\delta}

TL;DR

This study synthesizes a new iron-based superconductor LaFeAsO_{0.9}F_{0.1-elta} and investigates its critical magnetic field, Hall effect, and magnetoresistance, revealing electron-dominated conduction and anomalous scattering behaviors.

Contribution

First detailed measurements of upper critical field, Hall effect, and magnetoresistance in LaFeAsO_{0.9}F_{0.1-elta}, providing insights into its electronic properties and scattering mechanisms.

Findings

Upper critical field at zero temperature is about 50 Tesla.

Charge carrier density at 100 K is approximately 9.8E20 cm^{-3}.

Magnetoresistance does not follow Kohler's law and exhibits anomalous behavior around 230 K.

Abstract

By using a two-step method, we successfully synthesized the iron based new superconductor LaFeAsO_{0.9}F_{0.1-\delta}$. The resistive transition curves under different magnetic fields were measured, leading to the determination of the upper critical field Hc2(T) of this new superconductor. The value of Hc2 at zero temperature is estimated to be about 50 Tesla roughly. In addition, the Hall effect and magnetoresistance were measured in wide temperature region. A negative Hall coefficient R_H has been found, implying a dominant conduction mainly by electron-like charge carriers in this material. The charge carrier density determined at 100 K is about 9.8E20cm^{-3}, which is close to the cuprate superconductors. It is further found that the magnetoresistance does not follow Kohler's law. Meanwhile, the different temperature dependence behaviors of resistivity, Hall coefficient, and magnetoresistance have anomalous properties at about 230 K, which may be induced by some exotic scattering mechanism.