Resistance noise in uncoupled giant magnetoresistive multilayers

Various uncoupled, magnetoresistive multilayer systems show quasiequilibrium resistance noise associated with ‖dR(H)/dH‖. The size of this 1/f noise, particularly in comparison with Johnson noise in various frequency ranges, is discussed for all the different systems. All the observed samples exhibit resistive Barkhausen noise, allowing the measurement of domain sizes very similar to those observed in coupled samples. In addition, the asymmetric hysteresis of the Barkhausen noise in uncoupled multilayers suggests the same type of hysteretic domain structure observed in antiferromagnetically coupled multilayers.