An object of an aspect of the present invention is to provide: a lubricant excellent in adsorbability on the surface of a magnetic disk and in contamination resistance; and a magnetic disk which uses the lubricant and which is excellent in durability. The lubricant in accordance with an aspect of the present invention contains a fluoropolyether compound having, at a terminal thereof, a hydroxyalkenyl group or a hydroxyalkynyl group.

The invention provides a fullerene compound; a lubricant that is for a magnetic recording medium and that contains the fullerene compound; and a magnetic recording medium. The fullerene compound is an ionic liquid that is represented by general formula (1) and is formed from a Bronsted acid (H.sub.n1X) and a Bronsted base ([R.sub.2R.sub.3)N—].sub.m1—R.sub.1); wherein one of the Brønsted acid and the Broønsted base contains a group having a fullerene; and the other contains a perfluoroalkyl chain.

##STR00001##

Provided is a fluorine-containing ether compound that can be suitably used as a material for a lubricant for a magnetic recording medium, capable of forming a lubricant layer having excellent chemical substance resistance and wear resistance even when the thickness is small. A fluorine-containing ether compound represented by the following formula (1):

R.sup.1—R.sup.2—CH.sub.2—R.sup.3—CH.sub.2—R.sup.4—R.sup.5  (1)

In the formula (1), R.sup.3 is a perfluoropolyether chain. R.sup.2 and R.sup.4 are divalent linkage groups having a polar group, and may be the same or different. R.sup.1 and R.sup.5 are terminal groups bonded to R.sup.2 or R.sup.4, which may be the same or different, and at least one of R.sup.1 and R.sup.5 is an organic group having 1 to 8 carbon atoms wherein one or more hydrogen atoms of the organic group is substituted with a cyano group.

The present invention relates to a magnetic recording medium including a substrate; an underlayer laminated upon the substrate; and a magnetic layer laminated upon the underlayer, wherein the underlayer includes a first underlayer containing a compound represented by a following general formula: MgO.sub.(1-X), where X is within a range of 0.07 to 0.25, the magnetic layer includes a first magnetic layer containing an alloy having a L1.sub.0 structure, and the alloy having the L1.sub.0 structure includes B, and the first underlayer is in contact with the first magnetic layer.

A fluorine-containing ether compound characterized by being represented by the following formula (1):

R.sup.1—R.sup.2—CH.sub.2—R.sup.3—CH.sub.2—R.sup.4—R.sup.5  (1)

In the formula (1), R.sup.3 is a perfluoropolyether chain. R.sup.2 and R.sup.4 are divalent linkage groups having a polar group and may be the same or different. R.sup.1 and R.sup.5 are bonded to an atom other than a carbon atom of R.sup.2 or R.sup.4. R.sup.1 and R.sup.5 are terminal groups composed of an organic group having 1 to 8 carbon atoms and may be the same or different. At least one of R.sup.1 and R.sup.5 is a chain organic group having 1 to 8 carbon atoms wherein one or more hydrogen atoms of the chain organic group is substituted with a group having an amide bond.

This fluorine-containing ether compound is represented by Formula (1).
R.sup.1—R.sup.2—CH.sub.2—R.sup.3—CH.sub.2—R.sup.4—R.sup.5  (1) (in Formula (1), R.sup.1 is an aryl group or an aralkyl group, R.sup.2 is a divalent linking group having 0 or 1 polar group, R.sup.3 is a perfluoropolyether chain, R.sup.4 is a divalent linking group having 2 or 3 polar groups, and R.sup.5 is an aryl group or an aralkyl group.)

A fluorine-containing ether compound represented by the following formula (1).
C.sub.6H.sub.6-n—[O—R.sup.1—O—CH.sub.2—R.sup.2—CH.sub.2—R.sup.3].sub.n  (1)
(in the formula (1), n is an integer of 2 or 3, R.sup.1 is any one of —CH.sub.2CH.sub.2—, —CH.sub.2CH.sub.2CH.sub.2— and —CH.sub.2CH(OH)CH.sub.2—, R.sup.2 is a perfluoropolyether chain, R.sup.3 is —OCH.sub.2CH(OH)CH.sub.2O(CH.sub.2).sub.mOH (m in the formula is an integer of 2 to 4)).

The present invention is to provide an assisted magnetic recording medium including a substrate; an underlayer disposed on the substrate; a magnetic layer disposed on the underlayer and including an alloy having an L1.sub.0-type crystal structure; and a pinning layer disposed in contact with the magnetic layer, wherein the pinning layer includes a granular structure, the granular structure containing magnetic particles and grain boundaries, wherein the magnetic particles contain Co, and wherein the grain boundaries contain Y.sub.2O.sub.3 and/or an oxide of lanthanoid.

A fluorine-containing ether compound represented by R.sup.1R.sup.2CH.sub.2R.sup.3CH.sub.2R.sup.4R.sup.5 is provided. (R.sup.3 is a perfluoropolyether chain; R.sup.1 and R.sup.5 are each independently any one of an alkyl group that may have a substituent, an organic group having at least one double bond or at least one triple bond, and a hydrogen atom; and R.sup.2CH.sub.2R.sup.3 is represented by Formula (2), and R.sup.3CH.sub.2R.sup.4 is represented by Formula (3))

-[A]-[B]OCH.sub.2R.sup.3 (2)

R.sup.3CH.sub.2O[C]-[D]- (3)

([A] is represented by Formula (4), [B] is represented by Formula (5), [C] is represented by Formula (6), [D] is represented by Formula (7), and in the formula, a and b are integers of 0 to 2, c is an integer of 2 to 5, d and f are integers of 0 to 2, and e is an integer of 2 to 5, and at least one of b and d in the formula is 1 or more)

##STR00001##

A fluorine-containing ether compound represented by Formula (1) is provided,

R.sup.1-R.sup.2CH.sub.2R.sup.3CH.sub.2R.sup.4(1)

(In Formula (1), R.sup.1 is an alkyl group that may have a substituent, R.sup.2 is a divalent linking group bonded to R.sup.1 via an ethereal oxygen, R.sup.3 is a perfluoropolyether chain, and R.sup.4 is an end group which is different from R.sup.1-R.sup.2 and includes two or three polar groups, in which each of the polar groups is bonded to a different carbon atom, and the carbon atoms bonded to the polar groups are bonded to each other via a linking group containing a carbon atom not bonded to the polar groups.).