Improvement of recording performance in FePt perpendicular media by Ag pinning layer

With inserting one or two Ag layers, the FePt [001] preferred orientation is still maintained. The exchange coupling decreases, indicated by the decrease of the slope of the hysteresis loops at coercivity and significant increase of the coercivity as the Ag layer is inserted. The domain wall is effectively pinned by the Ag itself and some structure defects caused by the insertion of the Ag layer. The domain size decreases and the magnetic reversal tends to be a rotational mode as the thickness of the inserted Ag layer increases. The media noise is effectively reduced and the signal-to noise-ratio is remarkably enhanced when one 2-nm Ag is introduced.