We have investigated the room temperature 1/f noise of microstructured
soft magnetic Ni80Fe20 films, showing the anisotropic magnetoresistan
ce effect, and of Ni80Fe20/Cu magnetic multilayers, showing the giant
magnetoresistance effect. We find that the 1/f noise in magnetic multi
layers is considerably enhanced with respect to the noise of the singl
e domain layer, which sets a limit on the usability of giant magnetore
sistance materials for low-frequency applications. (C) 1996 American I
nstitute of Physics.