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High-quality thin polycrystalline films of the heavy-fermion compound CeCu 6 were prepared by sputter deposition. The thicker of these films ͑with thickness up to around 200 nm͒ reproduce the properties of the bulk compound CeCu 6 . As the thickness of the films is decreased, our measurements display strong deviations from the bulk properties, namely, a suppression of the heavy-fermion state. We show that possible ''external'' effects, such as disorder, oxidation and morphology can be excluded and that this size effect is therefore an intrinsic property of CeCu 6 . In addition, we investigate possible scenarios explaining the size effect, and find that the proximity of CeCu 6 to a quantum phase transition can account for this striking result.

Radio–frequency magnetron sputter epitaxy was employed for the synthesis of n–type modulation doped Si/Si1−xGex heterostructures. Si channels were grown coherently on sputtered, compositionally graded Si1−xGex buffers of low defect density, and remotely doped with phosphorus by plasma assisted gas phase doping. Magnetotransport measurements on these films revealed Shubnikov–de Haas oscillations in the longitudinal and the integer quantum Hall effect in the transverse magnetoresistance, demonstrating the presence of a two–dimensional electron gas. At T=1.6 K and sheet densities of 1012 cm−2, electron mobilities as high as 15 800 cm2/V s give evidence of the excellent structural and electronic properties achievable by the sputter growth technique.

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