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. ##STR00001##

Provided are a magnetic recording medium, in which a magnetic layer includes a ferromagnetic hexagonal ferrite powder, a binding agent, and an oxide abrasive, an intensity ratio Int(110)/Int(114) obtained by an X-ray diffraction analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0, a vertical squareness ratio of the magnetic recording medium is 0.65 to 1.00, a contact angle with respect to 1-bromonaphthalene measured regarding a surface of the magnetic layer is 50.0° to 55.0°, and an average particle diameter of the oxide abrasive obtained from a secondary ion image obtained by irradiating the surface of the magnetic layer with a focused ion beam is 0.04 μm to 0.08 μm, and a magnetic recording and reproducing device including this magnetic recording medium.

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.

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 less than 3.8.

A magnetic tape in which a CH derived C concentration calculated from a CH peak surface area ratio in C1s spectra obtained by XPS performed on a surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 atom % to 65 atom %, and in an environment with a temperature of 23 C. and a relative humidity of 50%, an AlFeSil abrasion value.sub.45 of the surface of the magnetic layer measured at a tilt angle of 45 of an AlFeSil prism is 20 m to 50 m, a standard deviation of an AlFeSil abrasion value of the surface of the magnetic layer measured at each of given tilt angles of the AlFeSil prism is 30 m or less, and the tilt angle of the AlFeSil prism is an angle formed by a longitudinal direction of the AlFeSil prism and a width direction of the magnetic tape.

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.

The magnetic recording medium includes: a non-magnetic support; and a magnetic layer including ferromagnetic powder, in which a difference S.sub.afterS.sub.before between a spacing S.sub.after measured on a surface of the magnetic layer by optical interferometry after methyl-ethyl-ketone cleaning and a spacing S.sub.before measured on the surface of the magnetic layer by optical interferometry before methyl-ethyl-ketone cleaning is more than 0 nm and 15.0 nm or less, and the non-magnetic support is an aromatic polyamide support having a moisture absorption of 2.2% or less.

The magnetic tape includes a non-magnetic support and a magnetic layer, in which the magnetic layer has a timing-based servo pattern, an edge shape of the timing-based servo pattern, specified by magnetic force microscopy is a shape in which a difference between a value L.sub.99.9 of a cumulative distribution function of 99.9% and a value L.sub.0.1 of a cumulative distribution function of 0.1% in a position deviation width from an ideal shape of the magnetic tape in a longitudinal direction is 180 nm or less, and a difference between a spacing S.sub.0.5 measured, after n-hexane cleaning, on a surface of the magnetic layer under a pressure of 0.5 atm by optical interferometry and a spacing S.sub.13.5 measured, after n-hexane cleaning, under a pressure of 13.5 atm is 3.0 nm or less, and S.sub.0.5 is 5.0 nm or more.

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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A method for producing a magnetic powder includes performing a reduction treatment on the surface of particles including a hard magnetic material to form core-shell particles each having a shell portion including a soft magnetic material.