Method for preparing a magnetic recording medium

A method for preparing a ferromagnetic thin metal film type magnetic recording medium comprising the steps of:

• depositing a metal vapor stream comprising Co as a main component on a non-magnetic support in an oxygen gas-containing atmosphere to form a ferromagnetic thin metal film, wherein said ferromagnetic thin metal film has an oxygen content of at least 15 at. %;
• treating the ferromagnetic thin metal film by holding it in an inert gas;
• and then
• applying a perfluoropolyether having an oxo acid group as a polar group to the ferromagnetic thin metal film;
• wherein said perfluoropolyether having an oxo acid group as a polar group has a saturation adsorption amount (mg/m.sup.2) of at least 4.0 mg/m.sup.2 against said ferromagnetic thin metal film.

A method for preparing a ferromagnetic thin metal film type magnetic recording medium comprising the steps of:

• depositing a metal vapor stream comprising Co as a main component on a non-magnetic support in an oxygen gas-containing atmosphere to form a ferromagnetic thin metal film, wherein said ferromagnetic thin meal film has an oxygen content of at least 15 at. %;
• holding the ferromagnetic thin metal film at a temperature of 100.degree. to 160.degree. C. for 1 to 60 seconds for heat-treatment;
• and then
• applying a perfluoropolyether having at least one polar group to the ferromagnetic thin metal film;
• wherein said perfluoropolyether having at least one polar group has a saturation adsorption amount (mg/m.sup.2) of at least 4.0 mg/m.sup.2 against said ferromagnetic thin metal film.