Aging Properties of Amorphous GdTbFeCo Magnetic Films and the Effect of Other Elements Added to Them

Tests on adding B, Bi, Al, Cr, Sm, and Cu to GdTbFeCo amorphous films revealed that B tends to reduce film deterioration and the Kerr rotation angle (θ
_K
). Cu or small amounts of Sm lowered the amount of coercive force (H
_c
) deterioration, but θ
_K
showed no substantial change. Cr had a larger effect than Sm, and also exhibited the smallest decrease in θ
_K
(to 73 percent of the original value after 100 h). The addition of Cr also lowered the Curie temperature as much as 70°C at 3.6 area%.