Submillisecond spin-stand measurements of thermal decay in magnetic recordings

The time dependence of magnetic recordings is determined on a spin stand by observing the amplitude of different spectral components of the readback signal from about 200 /spl mu/s to 11 s after writing. Measurement times shorter than one revolution period of the disk are obtained by placing separate write and read heads on the same track. An increased decay rate in the fundamental signal amplitude is observed at higher linear recording densities. The decay deviates from ln (t) at short times. Comparison of the decay rates of the spectral components of different density recordings indicates transition broadening over time.