Provided are: a magnetic recording medium including a non-magnetic support and a magnetic layer containing a ferromagnetic powder, in which the ferromagnetic powder is an ε-iron oxide powder, a vertical squareness ratio SQ of the magnetic recording medium is 0.50 or more and 0.95 or less at a measurement temperature of 25° C., and an inclination of SQ obtained from SQ at a measurement temperature of 10° C., SQ at a measurement temperature of 25° C., and SQ at a measurement temperature of 40° C. is −0.0050° C..sup.−1 or more and −0.0003° C..sup.−1 or less; a magnetic tape cartridge including the magnetic recording medium which is a magnetic tape; and a magnetic recording and reproducing device including the magnetic recording medium.

[Solving Means] A tape-shaped magnetic recording medium includes: a base; and a magnetic layer that is provided on the base and includes a magnetic powder. The magnetic powder includes magnetic particles that have a uniaxial crystal magnetic anisotropy and contain cobalt ferrite. A ratio L4/L2 of a component L4 having a multiaxial crystal magnetic anisotropy to a component L2 having a uniaxial crystal magnetic anisotropy is 0 or more and 0.25 or less, the components being obtained by applying Fourier transformation to a torque waveform of the magnetic recording medium.

[Object] To provide technologies such as an orientation device capable of increasing strength of a magnetic field in a transport path. [Solving Means] An orientation device according to the present technology includes a transport path, a permanent magnet portion, and a yoke portion. The transport path allows a base on which a magnetic coating film containing magnetic powder has been formed to pass through the transport path along a transport direction. The permanent magnet portion includes a plurality of first permanent magnets, and a plurality of second permanent magnets that is opposed to the plurality of first permanent magnets across the transport path in a vertical direction that is vertical to the transport direction in a manner that opposite poles face each other, the permanent magnet portion vertically orienting particles of the magnetic powder by applying a magnetic field to the magnetic coating film on the base that passes through the transport path. The yoke portion is made of a soft magnetic material, and connects to poles on a side opposite to the transport path side of the plurality of first permanent magnets, and to poles on a side opposite to the transport path side of the plurality of second permanent magnets.

The present disclosure provides where a magnetic recording medium is provided and includes a base; an underlayer that is provided over the base and includes a non-magnetic powder; and a magnetic layer that is provided over the underlayer and includes a magnetic powder and a binder, wherein an average particle volume V of the magnetic powder is 1600 nm.sup.3 or less, an average thickness of the magnetic recording medium is 5.3 μm or less, a thermal stability K.sub.uV.sub.act/k.sub.BT of the magnetic recording medium is 63 or more, and a ratio Hrp/Hc1 of a residual coercive force Hrp of the magnetic recording medium measured using a pulsed magnetic field in a perpendicular direction to a coercive force Hc1 of the magnetic recording medium in the perpendicular direction is 1.98 or less.

A magnetic recording medium is provided and includes a layer structure including a magnetic layer, a non-magnetic layer, and a base layer in this order, in which an average thickness t.sub.T of the magnetic recording medium is 3.5 μm≤t.sub.T≤5.3 μm, a dimensional variation Δw in a width direction of the magnetic recording medium to tension change in a longitudinal direction of the magnetic recording medium is 700 ppm/N≤Δw≤2000 ppm/N, and an average thickness t.sub.n of the non-magnetic layer is t.sub.n≤1.0 μm.

The magnetic tape includes a non-magnetic support, and a magnetic layer including a ferromagnetic powder. The number of recesses having an equivalent circle diameter of 0.30 μm to 0.60 μm existing on a surface of the magnetic layer is 10 to 600 per 40 μm×40 μm area, and a standard deviation σ of the number of recesses in a width direction on the surface of the magnetic layer is 100 or less.

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.

The magnetic tape in which the followings are satisfied, after the magnetic layer is pressed at a pressure of 70 atm. A full width at half maximum of a spacing distribution measured by optical interferometry regarding a surface of the magnetic layer before performing a vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 15.0 nm; a full width at half maximum of a spacing distribution measured after performing the vacuum heating is greater than 0 nm and equal to or smaller than 15.0 nm; and a difference (S.sub.after−S.sub.before) between a spacing S.sub.after measured by optical interferometry regarding the surface of the magnetic layer after performing the vacuum heating with respect to the magnetic tape and a spacing S.sub.before measured before performing the vacuum heating is greater than 0 nm and equal to or smaller than 12.0 nm.

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.

The magnetic tape includes a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, in which the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide, a C—H derived C concentration calculated from a C—H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on a surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is equal to or greater than 45 atom %, and an absolute value ΔN of a difference between a refractive index Nxy measured regarding an in-plane direction of the magnetic layer and a refractive index Nz measured regarding a thickness direction of the magnetic layer is 0.25 to 0.40.