Electromagnetic properties of thin epitaxial Bi films in magnetic fields up to 85 kG

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Abstract
Electromagnetic measurements on thin epitaxial Bi films (thickness: 350–6350 Å) were carried out in magnetic fields up to 85 kG. The transverse magnetoresistance had a tendency of saturation with increasing magnetic fields. The tendency was stronger for thinner films. This behavior was attributed to the scattering at the grain‐boundary planes parallel to the electric field. In the measurements of longitudinal magnetoresistance, the momentum value of carriers estimated from the positions of peaks or shoulders in the magnetoresistance–vs–magnetic‐field curve was about 0.8×10−21 g cm/sec and agrees with the bulk Bi value. The appearance of peaks or shoulders can be interpreted by the partial diffuse scattering of carriers at film surfaces. Shubnikov–de Haas oscillations were observed in (dρ/dH) ‐H measurements. The oscillation period Δ (H−1) was found to depend on film thickness and the dependence was attributed to the thickness dependence of carrier densities in films. The oscillations caused by quantum size effect were not observed.