An aspect of the present invention relates to a method of manufacturing hexagonal ferrite magnetic powder. The method of manufacturing hexagonal ferrite magnetic powder comprises wet processing hexagonal ferrite magnetic particles obtained following acid treatment in a water-based solvent to prepare an aqueous magnetic liquid satisfying relation (1) relative to an isoelectric point of the hexagonal ferrite magnetic particles: pH0pH*2.5, wherein, pH0 denotes the isoelectric point of the hexagonal ferrite magnetic particles and pH* denotes a pH of the aqueous magnetic liquid, which is a value of equal to or greater than 2.0, adding a surface-modifying agent comprising an alkyl group and a functional group that becomes an anionic group in the aqueous magnetic liquid to the aqueous magnetic liquid to subject the hexagonal ferrite magnetic particles to a surface-modifying treatment, and removing the water-based solvent following the surface-modifying treatment to obtain hexagonal ferrite magnetic particles.

An aspect of the present invention relates to a method of manufacturing hexagonal ferrite magnetic powder. The method of manufacturing hexagonal ferrite magnetic powder comprises wet processing hexagonal ferrite magnetic particles obtained following acid treatment in a water-based solvent to prepare an aqueous magnetic liquid satisfying relation (1) relative to an isoelectric point of the hexagonal ferrite magnetic particles: pH0pH*2.5, wherein, pH0 denotes the isoelectric point of the hexagonal ferrite magnetic particles and pH* denotes a pH of the aqueous magnetic liquid, which is a value of equal to or greater than 2.0, adding a surface-modifying agent comprising an alkyl group and a functional group that becomes an anionic group in the aqueous magnetic liquid to the aqueous magnetic liquid to subject the hexagonal ferrite magnetic particles to a surface-modifying treatment, and removing the water-based solvent following the surface-modifying treatment to obtain hexagonal ferrite magnetic particles.

The magnetic tape has a magnetic layer containing ferromagnetic powder and binder on a nonmagnetic support, wherein the centerline average surface roughness Ra as measured on the surface on the magnetic layer side of the magnetic tape is less than or equal to 1.8 nm, and the logarithmic decrement as determined by a pendulum viscoelasticity test on the surface on the magnetic layer side of the magnetic tape is less than or equal to 0.050.

The magnetic tape has a nonmagnetic layer containing nonmagnetic powder and binder on a nonmagnetic support, and has a magnetic layer containing ferromagnetic powder and binder on the nonmagnetic layer, wherein the combined thickness of the magnetic layer and the nonmagnetic layer is less than or equal to 0.80 m; and the logarithmic decrement as determined by a pendulum viscoelasticity test on the surface on the magnetic layer side of the magnetic tape is less than or equal to 0.050 and the coefficient of friction as measured on a base portion of the surface on the magnetic layer side is less than or equal to 0.35.

The magnetic tape has a magnetic layer containing ferromagnetic powder and binder on the surface on one side of a nonmagnetic support and has a backcoat layer containing nonmagnetic powder and binder on the surface on the other side of the nonmagnetic support, wherein the backcoat layer is less than or equal to 0.30 m in thickness; and the logarithmic decrement as determined by a pendulum viscoelasticity test on the surface on the backcoat layer side of the magnetic tape is less than or equal to 0.060.

The magnetic recording medium has a magnetic layer comprising ferromagnetic powder and binder on a nonmagnetic support, wherein the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, and the ferromagnetic hexagonal ferrite powder has a crystallite volume as determined by X-ray diffraction analysis ranges from 1,000 nm.sup.3 to 2,400 nm.sup.3, and a ratio of the crystallite size D.sub.x(107) obtained from a diffraction peak of a (107) plane to a particle size in a direction of an easy axis of magnetization D.sub.TEM as determined by observation with a transmission electron microscope, D.sub.x(107)/D.sub.TEM, is greater than or equal to 1.1.

The magnetic recording medium has a magnetic layer comprising ferromagnetic powder and binder on a nonmagnetic support, wherein the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, and the ferromagnetic hexagonal ferrite powder has a crystallite volume as determined by X-ray diffraction analysis ranges from 1,000 nm.sup.3 to 2,400 nm.sup.3, and a ratio of the crystallite size D.sub.x(107) obtained from a diffraction peak of a (107) plane to a particle size in a direction of an easy axis of magnetization D.sub.TEM as determined by observation with a transmission electron microscope, D.sub.x(107)/D.sub.TEM, is greater than or equal to 1.1.