Hall effect in laser ablated Co_2(Mn,Fe)Si thin films

TL;DR

This study investigates the Hall effect in laser-ablated Co_2(Mn,Fe)Si thin films, revealing temperature-independent normal Hall effect, skew scattering dominance, and a sign change with valence electron variation.

Contribution

It provides new insights into the Hall effect behavior and electronic structure of Heusler compound thin films grown by pulsed laser deposition.

Findings

Normal Hall effect is nearly temperature independent.

Anomalous Hall effect is dominated by skew scattering.

Sign change observed in Hall coefficients when changing from Mn to Fe.

Abstract

Pulsed laser deposition was employed to grow thin films of the Heusler compounds Co_2MnSi and Co_2FeSi. Epitaxial growth was realized both directly on MgO (100) and on a Cr or Fe buffer layer. Structural analysis by x-ray and electron diffraction shows for both materials the ordered L2_1 structure. Bulk magnetization was determined with a SQUID magnetometer. The values agree with the Slater-Pauling rule for half-metallic Heusler compounds. On the films grown directly on the substrate measurements of the Hall effect have been performed. The normal Hall effect is nearly temperature independent and points towards a compensated Fermi surface. The anomalous contribution is found to be dominated by skew scattering. A remarkable sign change of both normal and anomalous Hall coefficients is observed on changing the valence electron count from 29 (Mn) to 30 (Fe).