The magnetic recording medium has a magnetic layer containing multiple nonmagnetic particles having a ratio, major axis length/minor axis length, of less than or equal to 1.5, the multiple nonmagnetic particles are present in the magnetic layer in a state where, when the depth to which each of the multiple nonmagnetic particles is embedded in the magnetic layer in observation of a sectional image picked up by SEM is denoted as b and the thickness of the magnetic layer as t, the average value of the ratio of b/t is less than or equal to 0.9, and the number of protrusions 5 nm or greater in height is 800 or greater and the number of protrusions 20 nm or greater in height is 20 or less as measured by AFM per an area 40 μm×40 μm on the magnetic layer side surface of the magnetic recording medium.

The magnetic recording medium has a magnetic layer containing multiple nonmagnetic particles having a ratio, major axis length/minor axis length, of less than or equal to 1.5, the multiple nonmagnetic particles are present in the magnetic layer in a state where, when the depth to which each of the multiple nonmagnetic particles is embedded in the magnetic layer in observation of a sectional image picked up by SEM is denoted as b and the thickness of the magnetic layer as t, the average value of the ratio of b/t is less than or equal to 0.9, and the number of protrusions 5 nm or greater in height is 800 or greater and the number of protrusions 20 nm or greater in height is 20 or less as measured by AFM per an area 40 μm×40 μm on the magnetic layer side surface of the magnetic recording medium.

The magnetic tape 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 has a timing-based servo pattern, a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 1.8 nm, and an isoelectric point of a surface zeta potential of the magnetic layer is equal to or greater than 5.5.

The magnetic tape includes a non-magnetic support; a non-magnetic layer including a non-magnetic powder and a binding agent on the non-magnetic support; and a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic layer, in which a total thickness of the non-magnetic layer and the magnetic layer is equal to or smaller than 0.60 μm, the magnetic layer has a servo pattern, and an isoelectric point of a surface zeta potential of the magnetic layer 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 and a binding agent on the non-magnetic support, in which a difference (S.sub.0.5−S.sub.13.5) between a spacing S.sub.0.5 measured by optical interferometry regarding a surface of the magnetic layer under a pressing force of 0.5 atm after n-hexane cleaning and a spacing S.sub.13.5 measured by optical interferometry regarding the surface of the magnetic layer under a pressing force of 13.5 atm after n-hexane cleaning is equal to or smaller than 3.0 nm, and a magnetic recording and reproducing device including this magnetic recording medium.

A magnetic recording medium is a magnetic recording medium having a tape-like shape and includes a base substrate and a magnetic layer provided on the base substrate. A plurality of data tracks can be formed in the magnetic layer, a width of a data track is 2900 nm or less, and in a case of defining, as w.sub.max and w.sub.min, a maximum value and a minimum value respectively out of average values of a width of the magnetic recording medium measured under four kinds of environment in which temperature and relative humidity are set to (10° C., 10%), (10° C., 80%), (29° C., 80%), and (45° C., 10%), w.sub.max and w.sub.min satisfy a relation of (w.sub.max−w.sub.min)/w.sub.min≤400 [ppm].

A magnetic recording medium includes a substrate, a soft magnetic underlayer on the substrate, and a dual seed layer. The dual seed layer includes a first seed layer comprising NiFe at a first concentration, and a second seed layer comprising NiFe at a second concentration different from the first concentration and a segregant. The first seed layer may be on a soft magnetic underlayer and the second seed layer is on the first seed layer. The magnetic recording medium may further include one or more magnetic recording layers on the dual seed layer. The magnetic recording medium with the composition-graded dual seed layer may provide small grain size and good crystallographic texture for layers on the dual seed layer, including the magnetic recording layers.

An object is to further improve a thermal stability and an electromagnetic conversion characteristic of a magnetic recording medium.

The present technology provides a magnetic recording medium that includes a layer structure including: a base layer; and a magnetic layer provided on the base layer and including a magnetic powder, in which an average particle volume of the magnetic powder is 2300 nm.sup.3 or less, and a magnetic interaction ΔM calculated by the following expression (1) of the magnetic layer is −0.362≤ΔM≤−0.22,

ΔM={Id(H)+2Ir(H)−Ir(∞)}/Ir(∞)   (1)

[where, in the expression (1), Id(H) is a remanent magnetization measured by a direct-current demagnetization, Ir(H) is a remanent magnetization measured by an alternating-current demagnetization, and Ir(∞) is a remanent magnetization measured by an applied magnetic field of 6 kOe].

A magnetic recording medium is provided and includes a magnetic layer, a non-magnetic layer, a base layer and a back layer, wherein an average thickness t.sub.T of the magnetic recording medium is t.sub.T≤5.3 a dimensional change amount Δw in a width direction with respect to a change in tension in a longitudinal direction is 700 ppm/N≤Δw, a thickness of the non-magnetic layer is 2.0 μm or less, a squareness ratio measured in a vertical direction of the magnetic recording medium is 65% or more, and the magnetic layer includes a magnetic powder.

A magnetic recording medium is provided and includes a magnetic layer, a non-magnetic layer, a base layer and a back layer, wherein an average thickness t.sub.T of the magnetic recording medium is t.sub.T≤5.3 a dimensional change amount Δw in a width direction with respect to a change in tension in a longitudinal direction is 700 ppm/N≤Δw, a thickness of the non-magnetic layer is 2.0 μm or less, a squareness ratio measured in a vertical direction of the magnetic recording medium is 65% or more, and the magnetic layer includes a magnetic powder.