Patent ID: 7537846

Claim:
A magnetic disk having a magnetic layer formed on a nonmagnetic glass substrate and a protection layer formed on the magnetic layer, wherein: the protection layer contains carbon as a major component and is deposited by plasma CYD; the protection layer having a characteristic such that, when a spectrum is obtained by excluding photoluminescence from a Raman spectrum in a wavenumber band from 900 cm −1 to 1800 cm −1 obtained by exciting the protection layer with an argon ion laser beam having a wavelength of 514.5 nm and the spectrum is subjected to waveform separation by the Gaussian function to split a D peak appearing around 1350 cm −1 and a G peak appearing around 1520 cm −1 , the ratio Dw/Gw between a half width Dw of the D peak and a half width Gw of the G peak falls within a range between 2 and 2.7, wherein the protection layer has a film thickness within a range between 1 nm and 5 nm, a lubricant layer containing a perfluoropolyether compound having a hydroxyl group as a terminal group is deposited on the protection layer, and the magnetic disk is for use in a load unload system.