To provide a magnetic recording tape that exhibits excellent tape dimension stability even if there are changes in temperature or humidity or even if tension is applied to the magnetic recording tape during tape travelling.

The present technology provides a magnetic recording tape, the tape (T1 or T2) having a total thickness of 5.6 m or less and including a magnetic layer 1, a non-magnetic layer 2, a base layer 3, and a back layer 4 in the stated order. In one embodiment, a deposition film layer A formed of a metal or an oxide thereof is provided on a lower-layer side of the non-magnetic layer 2. The deposition film layer A may be provided on the back layer 4 and an insulation layer B may also be provided between the deposition film layer A the non-magnetic layer 2.

A tape-type magnetic recording medium, includes a substrate; and a magnetic layer provided on the substrate. The magnetic recording medium is configured such that (1) (w.sub.maxw.sub.min)/w.sub.min400 [ppm] where w.sub.max and w.sub.min are respectively maximum and minimum of average values of width of the magnetic recording medium measured under four environments whose temperature and relative humidity are (10 C., 10%), (10 C., 80%), (29 C., 80%), and (45 C., 10%), respectively, and the magnetic layer has a squareness ratio of 65% or more in the vertical direction, and (2) 4.4T.sub.B/(T.sub.AT.sub.B) where T.sub.A is an average thickness of the magnetic recording medium and T.sub.B is an average thickness of the substrate.

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 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.

The magnetic recording medium includes a non-magnetic support; and a magnetic layer including a ferromagnetic powder, in which the ferromagnetic powder is a ferromagnetic powder selected from the group consisting of a hexagonal strontium ferrite powder and an -iron oxide powder, the number of recesses having a depth which is or more of a minimum recording bit length existing on a surface of the magnetic layer is less than 10/10,000 m.sup.2, and a ratio d/t.sub.mag of a value d which is of the minimum recording bit length to a thickness t.sub.mag of the magnetic layer is 0.15 to 0.50.

The magnetic recording medium includes: a non-magnetic support; and a non-magnetic layer including a non-magnetic powder and a magnetic layer including a ferromagnetic powder on the non-magnetic support in this order, in which a vertical squareness ratio is 0.70 to 1.00, a center line average roughness Ra measured regarding a surface of the magnetic layer with an atomic force microscope is equal to or smaller than 2.5 nm, and an interface variation rate between the magnetic layer and the non-magnetic layer in a cross section image obtained by imaging with a scanning electron microscope is equal to or less than 2.5%.

The carbon black composition for manufacturing a particulate magnetic recording medium contains carbon black, vinyl chloride resin containing one or more epoxy groups, the secondary monoamine denoted by formula 1, and solvent, ##STR00001## wherein, in formula 1, each of R.sup.1 and R.sup.2 independently denotes an alkyl group branching off at a carbon atom, the carbon atom being present at an -position relative to an amine nitrogen atom, and having a main structure with 7 or fewer carbon atoms, it being possible for the alkyl group denoted by R.sup.1 to be in the form of a cyclic structure, possible for the alkyl group denoted by R.sup.2 to be in the form of a cyclic structure, and possible for the alkyl group denoted by R.sup.1 and the alkyl group denoted by R.sup.2 be connected to form a cyclic structure, with neither R.sup.1 nor R.sup.2 containing a hydroxyl group.

A magnetic recording medium includes: a substrate that is long in shape; and a magnetic layer containing magnetic powder and a binder. The glass transition point of the binder is not lower than 75 C. In a case where atomic force microscope observation images in a 10 m10 m rectangular shape are acquired at five locations randomly selected from the surface on the side of the magnetic layer, any linear protrusion that is 3 nm to 20 nm in height, is 0.3 m to 1.0 m in width, and extends across two sides of the observation image does not exist in the observation images of four locations among the acquired observation images of the five locations.

A magnetic tape in which an arithmetic average roughness Ra measured at a surface of a magnetic layer with an atomic force microscope is 2.0 nm or less, and in an environment with a temperature of 32 C. and a relative humidity of 80%, a frictional force F.sub.45 on the surface of the magnetic layer with respect to an LTO8 head measured at a head tilt angle of 45 is 4 gf to 15 gf, and a standard deviation of a frictional force F on the surface of the magnetic layer with respect to the LTO8 head measured at each of head tilt angles of 0, 15, 30, and 45 is 10 gf or less.

A magnetic tape in which a vertical switching field distribution SFD of the magnetic tape is 1.5 or less, and in an environment with a temperature of 32 C. and a relative humidity of 80%, a frictional force F.sub.45 on the surface of the magnetic layer with respect to an LTO8 head measured at a head tilt angle of 45 is 4 gf to 15 gf, and a standard deviation of a frictional force F on the surface of the magnetic layer with respect to the LTO8 head measured at each of head tilt angles of 0, 15, 30, and 45 is 10 gf or less.