Thermal noise, damping fundamentals and mode analysis: application to GMR sensors

Summary form only given. Magnetoresistive thin film sensors have been the dominant reason for the phenomenal growth in storage densities over the last decade. These sensors yield voltages when the direction of their ambient magnetization changes due to magnetic fields from the recorded media. A new source of noise has recently been found caused by thermal magnetization fluctuations of the film magnetization. These fluctuations yield random measurable voltages that add to the total system noise. Since thermal magnetization fluctuations vary inversely with the sensor volume, this noise source may dominate system performance at sufficiently high recording densities.