LAUSR

Abstract The characterization of the magnetic switching behavior of heat assisted magnetic recording (HAMR) media at near Curie temperature ( T c ) is important for high density recording. In this study, we measured the magnetic property of FePt granular media (with room temperature coercivity ~25 kOe) at near T c with a home built HAMR testing instrument. The local area of HAMR media is heated to near T c by a flat-top optical heating beam. The magnetic property in the heated area was in-situ measured by a magneto-optic Kerr effect (MOKE) testing beam. The switching field distribution (SFD) and coercive field ( H c ) of the FePt granular media and their dependence on the optical heating power at near T c were studied. We measured the DC demagnetization (DCD) signal with pulsed laser heating at different optical powers. We also measured the T c distribution of the media by measuring the AC magnetic signal as a function of optical heating power. In a summary, we studied the SFD, H c of the HAMR media at near T c in a static manner. The present methodology will facilitate the HAMR media testing.