The present technology provides a tape-shaped magnetic recording medium including a magnetic layer, an underlayer, a base layer, and a back layer. The magnetic recording medium has an average thickness t.sub.T of 5.4 μm or less, when a thermomechanical analysis is performed on the magnetic recording medium in a temperature range of 40° C. to 150° C. at a temperature rise rate of 1° C./minute, a switching temperature for switching from thermal expansion to thermal contraction is 70° C. or more, and a contraction start temperature is 90° C. or more at which a length in a longitudinal direction is shorter than the length at 40° C., and a Poisson's ratio is 0.40 or less.

The present technology provides a tape-shaped magnetic recording medium including a magnetic layer, an underlayer, a base layer, and a back layer. The magnetic recording medium has an average thickness t.sub.T of 5.4 μm or less, when a thermomechanical analysis is performed on the magnetic recording medium in a temperature range of 40° C. to 150° C. at a temperature rise rate of 1° C./minute, a switching temperature for switching from thermal expansion to thermal contraction is 70° C. or more, and a contraction start temperature is 90° C. or more at which a length in a longitudinal direction is shorter than the length at 40° C., and a Poisson's ratio is 0.40 or less.

The magnetic tape includes a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, in which the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide, a C—H derived C concentration calculated from a C—H peak area ratio of 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 is equal to or greater than 45 atom %, and an absolute value ΔN of a difference between a refractive index Nxy measured regarding an in-plane direction of the magnetic layer and a refractive index Nz measured regarding a thickness direction of the magnetic layer is 0.25 to 0.40.

The magnetic tape includes a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, in which the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide, a C—H derived C concentration calculated from a C—H peak area ratio of 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 is equal to or greater than 45 atom %, and an absolute value ΔN of a difference between a refractive index Nxy measured regarding an in-plane direction of the magnetic layer and a refractive index Nz measured regarding a thickness direction of the magnetic layer is 0.25 to 0.40.

A magnetic recording medium is a magnetic recording medium having a tape shape and includes a substrate, an underlayer provided on the substrate, and a magnetic layer provided on the underlayer. The magnetic layer has a surface having an uneven shape, a height range ΔH obtained from statistical information of a height of the uneven shape is in a range of 4.00 nm ≤ ΔH ≤ 10.00 nm, and a gradient range ΔA obtained from statistical information of a gradient of the uneven shape is in a range of 2.50 degrees ≤ ΔA.

A magnetic recording medium is a magnetic recording medium having a tape shape and includes a substrate, an underlayer provided on the substrate, and a magnetic layer provided on the underlayer. The magnetic layer has a surface having an uneven shape, a height range ΔH obtained from statistical information of a height of the uneven shape is in a range of 4.00 nm ≤ ΔH ≤ 10.00 nm, and a gradient range ΔA obtained from statistical information of a gradient of the uneven shape is in a range of 2.50 degrees ≤ ΔA.

The magnetic tape includes a non-magnetic support, and a magnetic layer including a ferromagnetic powder. The non-magnetic support is a polyethylene naphthalate support, and a deformation rate ratio of a deformation rate in a width direction to a deformation rate in a longitudinal direction of the magnetic tape, (the deformation rate in the width direction/the deformation rate in the longitudinal direction), is 0.42 or less, the deformation rates each being measured after a load is applied in the longitudinal direction of the magnetic tape for 96 hours.

The magnetic tape includes a non-magnetic support, and a magnetic layer including a ferromagnetic powder. The non-magnetic support is a polyethylene naphthalate support, and a deformation rate ratio of a deformation rate in a width direction to a deformation rate in a longitudinal direction of the magnetic tape, (the deformation rate in the width direction/the deformation rate in the longitudinal direction), is 0.42 or less, the deformation rates each being measured after a load is applied in the longitudinal direction of the magnetic tape for 96 hours.

A magnetic tape device. The angle θ formed by the axis of the element array of the magnetic head with respect to a width direction of the magnetic tape is changed during running of the magnetic tape in the magnetic tape device. In a case where a maximum value of an absolute value of a difference between a servo band spacing obtained before storage in a predetermined environment and a servo band spacing obtained after storage in the environment for a storage time T is defined as A, and T is set to a plurality of predetermined times, a medium life calculated by a linear function of A and a logarithm log.sub.e T of T, that are derived from a value of A and a value of the logarithm log.sub.e T of T obtained for each T is 5 years or longer.

A magnetic tape device. The angle θ formed by the axis of the element array of the magnetic head with respect to a width direction of the magnetic tape is changed during running of the magnetic tape in the magnetic tape device. In a case where a maximum value of an absolute value of a difference between a servo band spacing obtained before storage in a predetermined environment and a servo band spacing obtained after storage in the environment for a storage time T is defined as A, and T is set to a plurality of predetermined times, a medium life calculated by a linear function of A and a logarithm log.sub.e T of T, that are derived from a value of A and a value of the logarithm log.sub.e T of T obtained for each T is 5 years or longer.