The average thickness t.sub.T of a magnetic recording medium meets the requirement that t.sub.T≤5.5 [μm], and the dimensional change amount Δw in the width direction of the magnetic recording medium with respect to the tension change in the longitudinal direction of the magnetic recording medium meets the requirement that 700 ppm/N≤Δw.

The magnetic tape includes a non-magnetic support, a magnetic layer that includes ferromagnetic powder having an average particle volume of 2,500 nm.sup.3 or less on one surface side of the non-magnetic support, and a back coating layer that includes non-magnetic powder on the other surface side of the non-magnetic support, in which the ferromagnetic powder is ferromagnetic powder selected from the group consisting of hexagonal ferrite powder and ε-iron oxide powder, and a ratio (PSD.sub.5 μm-PSDmag/PSD.sub.10 μm-PSDbc) of the magnetic layer and the back coating layer is in a range of 0.0050 to 0.20. A magnetic tape cartridge and a magnetic recording and reproducing apparatus include the magnetic tape.

The magnetic tape includes a non-magnetic support, a magnetic layer that includes ferromagnetic powder having an average particle volume of 2,500 nm.sup.3 or less on one surface side of the non-magnetic support, and a back coating layer that includes non-magnetic powder on the other surface side of the non-magnetic support, in which the ferromagnetic powder is ferromagnetic powder selected from the group consisting of hexagonal ferrite powder and ε-iron oxide powder, and a ratio (PSD.sub.5 μm-PSDmag/PSD.sub.10 μm-PSDbc) of the magnetic layer and the back coating layer is in a range of 0.0050 to 0.20. A magnetic tape cartridge and a magnetic recording and reproducing apparatus include the magnetic tape.

The magnetic tape includes a non-magnetic support and a magnetic layer including a ferromagnetic powder, in which in an environment of a temperature of 32° C. and a relative humidity of 80%, a frictional force F.sub.0.2 N on a magnetic layer surface with respect to an LTO8 head, which is measured by applying a tension of 0.2 N in a longitudinal direction of the magnetic tape, is in a range of 4 to 15 gf, and a frictional force F.sub.1.5 N on the magnetic layer surface with respect to the LTO8 head, which is measured by applying a tension of 1.5 N in the longitudinal direction of the magnetic tape, is in a range of 4 to 15 gf.

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.

This technology aims to provide a magnetic recording tape and the like, which allow the tape to stably run at high speed while maintaining a state in which the distance between a magnetic head and the tape is held narrow.

This technology provides a magnetic recording tape having a plural-layer structure including at least a magnetic layer. The tape has a total thickness of 5.6 μm or smaller, and includes a plurality of indentations disposed in a surface of the magnetic layer. A value obtained by dividing a depth D1 of each indentation with a thickness D2 of the magnetic layer is 15% or greater. The magnetic layer is perpendicularly oriented, and has a perpendicular orientation of 65% or greater under condition of no demagnetization correction. The magnetic layer includes a plurality of indentations formed therein, a plurality of the indentations each has a depth of 20% or greater of the thickness of the magnetic layer, and the number of the indentations is 55 or more per 6,400 μm.sup.2 of a surface area of the magnetic layer. This technology also provides a manufacturing method of the magnetic recording tape.

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 m40 m 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 m40 m on the magnetic layer side surface of the magnetic recording medium.

The average thickness t.sub.T of a magnetic recording medium meets the requirement that t.sub.T5.5 [m], and the dimensional change amount w in the width direction of the magnetic recording medium with respect to the tension change in the longitudinal direction of the magnetic recording medium meets the requirement that 700 ppm/Nw.