Hall effect in laser ablated Co2(Mn,Fe)Si thin films

Pulsed laser deposition was employed to grow thin films of the Heusler compounds Co2MnSi and Co2FeSi. Epitaxial growth was realized both directly on MgO(1 0 0) and on a Cr or Fe buffer layer. Structural analysis by x-ray and electron diffraction shows for both materials the ordered L21 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 in both normal and anomalous Hall coefficients is observed on changing the valence electron count from 29 (Mn) to 30 (Fe).

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