Galvanomagnetic behavior of semiconducting FeSi2 films

Abstract
Hall-effect measurements in magnetic fields up to 1.5 T are performed on β-FeSi2 films between 20 and 300 K. An anomalous low-field Hall coefficient R1 in addition to the normal high-field Hall coefficient R0 is detected at temperatures below 250 K. The temperature dependence of R0 is explained by a two valence-band model and an impurity level located close to the upper valence-band edge. The temperature dependence of R1 indicates that β-FeSi2 behaves as ferromagnetic below 100 K. Correlation between the coefficient Rs=R1−R0 and the electrical resistivity ρ indicates a drastic change in magnetic ordering at about 70 K.