Magneto-Transport Properties of Single Crystalline LaFeAsO

TL;DR

This study investigates the magneto-transport properties of single crystalline LaFeAsO, revealing features of structural transition and spin density wave order, with detailed measurements of resistivity, Hall effect, and magnetoresistance.

Contribution

It provides new insights into the magneto-transport behavior of single crystalline LaFeAsO, including the effects of structural transition and SDW formation, with detailed experimental data.

Findings

Charge carriers are electrons with high mobility.

Structural transition occurs near 140 K, lower than in polycrystalline samples.

Magnetoresistivity scales with magnetic field and temperature.

Abstract

Measurements of magnetization, specific heat, electrical resistivity, Hall effect, and magnetoresistance on single crystalline samples of LaFeAsO grown in a NaAs flux are reported. While this material is known to be a semimetal, the temperature dependence of the electrical resistivity data presented herein is reminiscent of semiconducting behavior and exhibits distinct features associated with a structural transition and spin density wave (SDW) order. Magnetoresistance and Hall coefficient measurements were performed in magnetic fields up to 9 T applied perpendicular to the basal plane using a van der Pauw configuration. The charge carrier density and mobility indicate that electrons are the majority charge carriers and exhibit features indicative of the structural transition and SDW formation. Low temperature X-ray diffraction measurements have confirmed that the structural transition in these samples occurs near 140 K, compared to a transition temperature of 156 K observed in polycrystalline samples. Isotherms of magnetoresistivity measured as a function of magnetic field can be scaled onto a single curve in which the scaling field is a linear function of temperature between 2.2 K and 180 K.