Magnetoresistance of small, quasi-one-dimensional, normal-metal rings and lines

The magnetoresistance of sub-0.4-\ensuremath{\mu}m-diam Au and ${\mathrm{Au}}_{60}$${\mathrm{Pd}}_{40}$ rings was measured in a perpendicular magnetic field at temperatures as low as 5 mK in search of simple, periodic resistance oscillations that would be evidence of flux quantization in normal-metal rings. However, instead of simple oscillations, a very complex structure developed in the magnetoresistance at low temperatures. Fourier analysis of all the data did not reveal convincing evidence for flux quantization in the rings. Complex structure similar to that observed in the rings was also found in the magnetoresistance of short, narrow, Au and ${\mathrm{Au}}_{60}$${\mathrm{Pd}}_{40}$ lines. This structure appears to be associated with the small size of the devices.