The magnetic tape includes a magnetic layer having ferromagnetic powder and a binder on a non-magnetic support, in which the magnetic layer includes a timing-based servo pattern, the ferromagnetic powder is ferromagnetic hexagonal ferrite powder having an activation volume equal to or smaller than 1,600 nm.sup.3, and an edge shape of the timing-based servo pattern specified by a magnetic force microscope observation is a shape in which a difference (l.sub.99.9−l.sub.0.1) between a value l.sub.99.9 of a cumulative frequency function of 99.9% of a position deviation width from an ideal shape in a longitudinal direction of the magnetic tape and a value l.sub.0.1 of the cumulative frequency function of 0.1% thereof is equal to or smaller than 180 nm.

A magnetic recording medium is a tape-shaped magnetic recording medium, including: a substrate; an underlayer provided on the substrate; and a magnetic layer provided on the underlayer. The substrate contains polyester, each of the underlayer and the magnetic layer contains a lubricant, the magnetic layer has a surface on which a large number of holes is provided, the arithmetic average roughness Ra of the surface is 2.5 nm or less, a BET specific surface area of the entire magnetic recording medium measured in a state where the magnetic recording medium has been washed and dried is 3.5 m.sup.2/g or more and 7.0 m.sup.2/g or less, a squareness ratio of the magnetic layer in a vertical direction is 65% or more, an average thickness of the magnetic layer is 80 nm or less, an average thickness of the magnetic recording medium is 5.6 μm or less, and a servo pattern is recorded on the magnetic layer and a statistical value δ.sub.SW indicating a non-linearity of the servo pattern is 24 nm or less.

The magnetic tape cartridge includes a magnetic tape, and a cartridge reel. In the magnetic tape, a minimum winding deviation occurrence load measured after the magnetic tape is rewound around the cartridge reel by applying a tension of 0.40 N in a longitudinal direction of the magnetic tape is 300 N or less.

The present technology provides a tape-shaped magnetic recording medium including: a magnetic layer; an underlayer; a base layer; and a back layer, in which the number of recesses having a depth of 20% or more of the thickness of the magnetic layer is 10 or more and 200 or less per surface area of 1600 μm.sup.2, the base layer includes a polyester as a main component, a surface on a side of the back layer has a kurtosis of 2.0 or more and 4.4 or less, the magnetic recording medium has an average thickness t.sub.T of 5.6 μm or less, the magnetic recording medium includes a lubricant, the magnetic recording medium has pores, and the pores have an average diameter of 6 nm or more and 11 nm or less when the diameters of the pores are measured in a state where the lubricant has been removed from the magnetic recording medium and the magnetic recording medium has been dried.

In the magnetic recording medium, a number distribution A of a plurality of bright regions, based on equivalent circle diameters thereof, in a binarized image of a secondary electron image obtained by imaging a surface of the magnetic layer by a scanning electron microscope at an acceleration voltage of 5 kV and a number distribution B of a plurality of dark regions, based on equivalent circle diameters thereof, in a binarized image of a secondary electron image obtained by imaging a surface of the magnetic layer by a scanning electron microscope at an acceleration voltage of 2 kV respectively satisfy a predetermined number distribution.

A magnetic recording medium includes: a substrate; and a magnetic layer including a ferrimagnetic particle powder. A product (V×SFD) of a particle volume V and a holding force distribution SFD of the ferrimagnetic particle is equal to or less than 2500 nm3.

The magnetic recording medium includes: a non-magnetic support; and a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic support, in which the magnetic layer further includes a compound including a polyalkyleneimine chain and a vinyl polymer chain. The composition for a magnetic recording medium includes: ferromagnetic powder; and a compound including a polyalkyleneimine chain and a vinyl polymer chain.

Provided is a magnetic tape cartridge of a single reel type in which a magnetic tape is wound around a reel, in which the magnetic tape includes a non-magnetic support and a magnetic layer containing a ferromagnetic powder, and has a tape thickness of 5.3 μm or less, the magnetic layer includes a plurality of servo bands, and a difference (G.sub.inner−G.sub.outer) between a servo band interval G.sub.inner in a range of 49 m to 51 m from a tape inner end and a servo band interval G.sub.outer in a range of 49 m to 51 m from a tape outer end is −3.9 μm to −1.1 μm as a value measured on 100th day from a date of magnetic tape cartridge manufacture.

A production method for metal oxide particles includes: obtaining precursor particles of a metal oxide by performing a synthesis reaction of the precursor particles in the presence of an organic compound; and converting the obtained precursor particles into metal oxide particles by heating an aqueous solution containing the precursor particles to 300° C. or higher and pressurizing the aqueous solution at a pressure of 20 MPa or higher.

The hexagonal ferrite powder has an activation volume of greater than or equal to 800 nm.sup.3 but less than 1,200 nm.sup.3, a rare earth atom content falling within a range of 0.5 to 8.0 atom % per 100 atom % of iron atoms, and a localized presence of rare earth atoms in the surface layer portion, as well as is in the form of ellipsoidal powder.