1/f noise in saturated GMR heads

The extra-low-frequency noise of GMR heads was measured at large saturation fields (similar to 10 kOe). It was 1/f in nature. The head resistance incr eased exponentially with applied cumulative voltage pubes when the amplitud e was larger than 1 V, However, the noise did not change even after the hea d resistance increased by 18%. This could be explained if the noise was gen erated mostly from the contiguous junction areas. A supra-linear dependence of noise voltage on sense current was observed. The supra-linearity increa sed after the sensor height was reduced by lapping. Hooge's formula was sho wn to apply at low currents. The excessive noise at high currents and at re duced sensor height was attributed to current crowding, in particular, curr ent crowding caused by current heating.