Quantifying Side Reading in Heat-Assisted Magnetic Recording

Heat-assisted magnetic recording (HAMR) can write narrow tracks and achieves maximal areal density at track pitches narrower than the effective reader width, leading to significant side reading. To assess the mechanism, spin stand tests have been developed to capture the noise-free waveforms from side reading, resolve the in-phase and anti-phase components, and generate reader sensitivity profiles with both amplitude and phase information. The testing results of two types of readers with different widths but the same side reading from background interference show that side reading not only depends on the shape of the reader sensitivity profile, including the width of the main peak and the magnitude and location of the undershoots, but also on how the profile overlays with the background tracks.