Experimental measurements and analysis of thermal magnetization noise in GMR sensors

High-frequency measurements and theoretical analysis of data on giant magnetoresistance thermal magnetization fluctuation noise are presented. An experimental setup for the measurement of this noise at high frequencies is proposed. The measured noise increases with bias current and demonstrates two distinct resonance peaks within 6 GHz. Damping parameters are extracted from resonance linewidth data. Small variations are seen within a given manufacturing batch of eight heads. Data fitting to the measured-noise power spectrum and comparison between eigenmode and Landau-Lifshitz-Gilbert theories.