Magnetotransport properties in semimetallic bismuth thin films

The magnetotransport properties of the electroplated and sputtered Bi thin films have been investigated in the range 4 - 300 K. A marked increase from 5,200 % to 80,000 % in the ordinary magnetoresistance (MR) for the electroplated Bi thin film was observed after thermal anneal at 4 K. The MR ratios for the as-grown and the annealed Bi thin films were found to exhibit 560 % and 590 %, respectively, at 300 K. On the other hand, the MR for the sputtered Bi film grown by sputtering was hardly observed at 4 and 300 K, whereas the MR ratios after anneal were found to reach 30,000 % at 4 K and 600 % at 300 K. We find that the room temperature MR in the sputtered films depends on the trigonal-axis oriented microstructures and grain size, in contrast to the electroplated films. Our results demonstrate the very large room temperature MR in the electroplated and sputtered Bi thin films, which can be used for spintronic device applications.