NEGATIVE MAGNETORESISTANCE AS A RESULT OF HOPPING CONDUCTION IN POLYCRYSTALLINE THIN-FILMS OF BETA-FESI2

Low-temperature negative magnetoresistance has been measured in polycr ystalline thin films of semiconducting iron disilicide prepared by pul sed laser deposition. The onset of negative magnetoresistance occurs a t a temperature of similar to 20 K and increases with decreasing tempe rature. No saturation is observed in the magnetoresistance, which disp lays an H-2 behavior for magnetic-field values below 8 kOe, and an H-1 /2 behavior for higher values through 55 kOe. Resistivity measurements indicate that hopping conduction becomes the transport mechanism belo w similar to 200 K and is therefore assumed to be responsible for the negative magnetoresistance.