The magnetic tape includes a non-magnetic support, and a magnetic layer including a ferromagnetic powder. A fluorine-containing compound is included in a portion on the non-magnetic support on a magnetic layer side, and a ratio r of a water contact angle measured on a surface of the magnetic layer after sliding on a magnetic head to a water contact angle measured on the surface of the magnetic layer before sliding on the magnetic head is 0.70 or more.

A magnetic recording cartridge includes a magnetic recording medium of which an average thickness t.sub.T is t.sub.T5.6 m, a dimensional change amount w in a width direction with respect to a tension change in a longitudinal direction is 660 ppm/Nw, and a squareness ratio in a vertical direction is 65% or more, in which the magnetic recording medium is accommodated in a state of being wound around a reel and (a servo track width on an inner side of winding of the magnetic recording medium)(a servo track width on an outer side of winding of the magnetic recording medium)>0 is satisfied.

A magnetic recording cartridge is provided and including a magnetic recording medium, wherein an average thickness of the magnetic recording medium t.sub.T is 3.5 mt.sub.T 5.6 m, a dimensional change amount w in a width direction of the magnetic recording medium with respect to a tension change in a longitudinal direction of the magnetic recording medium is 700 ppm/Nw 20000 ppm, the magnetic recording medium is accommodated in a state of being wound around the reel in the cartridge case and (a servo track width on an inner side of winding of the magnetic recording medium)-(a servo track width on an outer side of winding of the magnetic recording medium) > is satisfied, and a squareness ratio measured in a vertical direction of the magnetic recording medium is 65% or more.

A magnetic recording cartridge includes a magnetic recording medium of which an average thickness t.sub.T is t.sub.T5.6 m, a dimensional change amount w in a width direction with respect to a tension change in a longitudinal direction is 660 ppm/Nw, and a squareness ratio in a vertical direction is 65% or more, in which the magnetic recording medium is accommodated in a state of being wound around a reel and (a servo track width on an inner side of winding of the magnetic recording medium)(a servo track width on an outer side of winding of the magnetic recording medium)>0 is satisfied.

A magnetic recording medium includes a layer structure including a magnetic layer, a base layer, and a back layer in this order, in which an average thickness t.sub.T is t.sub.T5.5 m, a dimensional variation w in a width direction to tension change in a longitudinal direction is 660 ppm/Nw, and a surface roughness R.sub.abe of the base layer on a side of the back layer is 4.2 nmR.sub.abe8.5 nm.

A magnetic recording medium includes: an elongated substrate having flexibility; a first layer, being provided on the substrate, containing Cr, Ni, and Fe, and having a face-centered cubic lattice structure with a (111) plane preferentially oriented so as to be parallel to a surface of the substrate; a second layer, being provided on the first layer, containing Co and O, having a ratio of an average atomic concentration of O to an average atomic concentration of Co of 1 or more, and having a column structure with an average particle diameter of 3 nm or more and 13 nm or less; a third layer, being provided on the second layer, and containing Ru; and a perpendicular recording layer, being provided on the third layer.

A magnetic recording cartridge is provided and including a magnetic recording medium, wherein an average thickness of the magnetic recording medium t.sub.T is 3.5 mt.sub.T5.6 m, a dimensional change amount w in a width direction of the magnetic recording medium with respect to a tension change in a longitudinal direction of the magnetic recording medium is 700 ppm/Nw20000 ppm, and the magnetic recording medium is accommodated in a state of being wound around the reel in the cartridge case and (a servo track width on an inner side of winding of the magnetic recording medium)(a servo track width on an outer side of winding of the magnetic recording medium)>0 is satisfied.

A magnetic recording medium includes a long-shaped base substrate having flexibility, a soft magnetic layer, and a magnetic recording layer. A squareness ratio in a longitudinal direction of the base substrate is equal to or less than a squareness ratio in a short-side direction of the base substrate. The squareness ratio in the longitudinal direction of the base substrate is 30% or less.

A fluorine-containing ether compound represented by the following formula (1) is provided.

R.sup.2CH.sub.2R.sup.1CH.sub.2OCH.sub.2CH(OH)(CH.sub.2).sub.nCH(OH)CH.sub.2OCH.sub.2R.sup.1CH.sub.2R.sup.2(1)

(in the formula (1), n is an integer of 2 to 6, R.sup.1 is a perfluoropolyether chain, R.sup.2 is OCH.sub.2CH(OH)CH.sub.2O(CH.sub.2).sub.mOH (m in the formula is an integer of 2 to 4)).

A magnetic recording medium includes: an elongated substrate having flexibility; a first layer, being provided on the substrate, containing Cr, Ni, and Fe, and having a face-centered cubic lattice structure with a (111) plane preferentially oriented so as to be parallel to a surface of the substrate; a second layer, being provided on the first layer, containing Co and O, having a ratio of an average atomic concentration of O to an average atomic concentration of Co of 1 or more, and having a column structure with an average particle diameter of 3 nm or more and 13 nm or less; a third layer, being provided on the second layer, and containing Ru; and a perpendicular recording layer, being provided on the third layer.