The magnetic recording medium includes a non-magnetic support; and a magnetic layer including a ferromagnetic powder, in which one or more kinds of component selected from the group consisting of a fatty acid and a fatty acid amide are included in a portion of the magnetic layer side on the non-magnetic support, and a CH derived C concentration calculated from a CH peak surface area ratio in 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, after pressing the magnetic layer at a pressure of 70 atm is 45 atom % or more.

The magnetic recording medium includes a non-magnetic support; and a magnetic layer including a ferromagnetic powder, in which an isoelectric point of a surface zeta potential of the magnetic layer after pressing the magnetic layer at a pressure of 70 atm is equal to or greater than 5.5.

A tape cartridge, according to one approach, includes a housing, and a magnetic recording tape at least partially stored in the housing. The magnetic recording tape including a recording layer having encapsulated nanoparticles each comprising a magnetic nanoparticle encapsulated by an encapsulating layer, and a polymeric binder binding the encapsulated nanoparticles. A tape cartridge, according to another approach, includes a housing, and a magnetic recording tape at least partially stored in the housing. The magnetic recording tape include an underlayer having encapsulated nanoparticles each comprising a magnetic nanoparticle encapsulated by an aromatic polymer, and a polymeric binder binding the encapsulated nanoparticles.

[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 magnetic recording medium includes: a non-magnetic support; and a magnetic layer including ferromagnetic powder, in which the magnetic layer includes a compound having a salt structure, and the salt structure is an ammonium salt structure of an alkyl ester anion represented by the following Formula 1. In Formula 1, R represents an alkyl group having 7 or more carbon atoms or a fluorinated alkyl group having 7 or more carbon atoms, Z.sup.+ represents an ammonium cation, and a water contact angle on a surface of the magnetic layer is 80 or more and less than 100. A magnetic recording and reproducing apparatus includes the magnetic recording medium.

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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.afterS.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 tape has a nonmagnetic layer containing nonmagnetic powder and binder on a nonmagnetic support, and a magnetic layer containing ferromagnetic powder and binder on the nonmagnetic layer; wherein the combined thickness of the nonmagnetic layer and the magnetic layer is less than or equal to 0.60 m, the coefficient of friction as measured on the base portion of the surface of the magnetic layer is less than or equal to 0.35, at least the magnetic layer contains one or more components selected from the group consisting of a fatty acid and a fatty acid amide, and a CH derived carbon, C, concentration calculated from a CH peak area ratio in a C1s spectrum obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 10 degrees on the surface of the magnetic layer is greater than or equal to 45 atom %.

Provided is a magnetic tape device in which a magnetic tape transportation speed is equal to or lower than 18 m/sec, Ra measured regarding a surface of a magnetic layer of a magnetic tape is equal to or smaller than 2.0 nm, a CH derived C concentration calculated from a CH peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %, and SFD (=SFD.sub.25C.SFD.sub.190 C.) in a longitudinal direction of the magnetic tape is equal to or smaller than 0.50, with the SFD.sub.25 C. being SFD measured in a longitudinal direction of the magnetic tape at a temperature of 25 C., and the SFD.sub.190 C. being SFD measured at a temperature of 190 C.

A magnetic tape has a total thickness of a non-magnetic layer and a magnetic layer of 0.60 m or smaller. The magnetic layer includes an abrasive and fatty acid ester. The percentage of a plan view maximum area of the abrasive confirmed in a region having a size of 4.3 m6.3 m of the surface of the magnetic layer with respect to the total area of the region, obtained by plane observation performed by using an SEM is 0.02% or greater and less than 0.06%. The full widths at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer before and after performing a vacuum heating with respect to the magnetic tape are greater than 0 nm and 7.0 nm or smaller, and the difference between spacings before and after the vacuum heating is greater than 0 nm and is 8.0 nm or smaller.

Disclosed are a particle of a 13-iron oxyhydroxide-based compound represented by Formula (1), in which an average equivalent circle diameter of primary particles is 5 nm to 30 nm, and a coefficient of variation of equivalent circle diameters of the primary particles is 10% to 30% [In Formula (1), A represents at least one kind of metal element other than Fe, and a represents a number that satisfies a relationship of 0a<1.], and applications thereof.

-A.sub.aFe.sub.1-aOOH (1)