LOW-TEMPERATURE ELECTRIC AND MAGNETIC STUDIES OF PERMALLOY THIN-FILMS

Permalloy thin films with thickness between 5 nm and 400 mu m were gro wn on Si(100) wafers by DC magnetron sputtering. Electric resistivity and magnetoresistance were studied between 4 and 300 K. With decreasin g temperature the electric resistivity decreases, but the magnetoresis tance (MR) ratio is found to increase. The MR ratio at room temperatur e varies between 0.3 and 3.1% for samples with thickness between 5 nm and 400 mu m. The maximum MR ratio measured at 4.2 K is approximately 7%. The grain size increases with increasing thickness of the films an d we show that this effect leads to a decrease in the electric resisti vity and to an increase in the MR ratio.