In the magnetic tape, a magnetic tape deformation amount after storage for 3 months each in a predetermined environment is 0.50 μm or less, a rate of a change in the magnetic tape deformation amount with respect to a change in relative humidity is 0.0001 μm/% to 0.0500 μm/%, and a rate of a change in magnetic tape deformation amount with respect to a change in temperature is 0.0010 μm/° C. to 0.1000 μm/° C.

Provided are a magnetic tape comprising a magnetic layer containing a ferromagnetic powder and a binding agent on a non-magnetic support, in which the magnetic layer contains an oxide abrasive, an average particle diameter of the oxide abrasive obtained from a secondary ion image acquired by irradiating a surface of the magnetic layer with a focused ion beam is greater than 0.08 μm and 0.14 μm or smaller, and an absolute value ΔN of a difference between a refractive index Nxy measured with respect to an in-plane direction of the magnetic layer and a refractive index Nz measured with respect to a thickness direction of the magnetic layer is 0.25 to 0.40, and a magnetic recording and reproducing device including the magnetic tape.

The magnetic recording medium includes a non-magnetic support; and a magnetic layer including a ferromagnetic powder, in which the ferromagnetic powder is a ferromagnetic powder selected from the group consisting of a hexagonal strontium ferrite powder and an ε-iron oxide powder, the number of recesses having a depth which is ⅓ or more of a minimum recording bit length existing on a surface of the magnetic layer is less than 10/10,000 μm.sup.2, and a ratio d/t.sub.mag of a value d which is ⅓ of the minimum recording bit length to a thickness t.sub.mag of the magnetic layer is 0.15 to 0.50.

In the magnetic tape, in a case where a maximum value of an absolute value of a difference between a servo band spacing obtained before storage in an environment of a temperature of 32° C. and relative humidity of 55% and a servo band spacing obtained after storage in the environment for a storage time T is set to A, and T is defined as 24 hours, 48 hours, 72 hours, 96 hours, or 120 hours, a medium life calculated by a linear function of A and a logarithm log.sub.eT of T, that are derived from a value of A and a value of the logarithm log.sub.eT of T obtained for each T is 3 years or longer. The medium life is T in a case where the A satisfies Equation 1: A=1.5−B.

A magnetic recording medium, which is used in a recording and playback device in which the shortest recording wavelength is 75 nm or less, in which the magnetic recording medium has a recording layer including powder of ε-iron oxide-containing particles, the average particle size of the particles is 22 nm or less, the coercive force He is 220 kA/m or more and 320 kA/m or less, and the non linear transition shift is 20% or less.

A magnetic recording medium, which is used in a recording and playback device in which the shortest recording wavelength is 75 nm or less, in which the magnetic recording medium has a recording layer including powder of ε-iron oxide-containing particles, the average particle size of the particles is 22 nm or less, the coercive force He is 220 kA/m or more and 320 kA/m or less, and the non linear transition shift is 20% or less.

Provided is a recording device. The recording device includes: an external magnetic field application unit that is configured to apply an external magnetic field to a magnetic recording medium; a light irradiation unit that is configured to irradiate light; and a light focusing unit that is configured to focus the light from the light irradiation unit by resonating the light to generate an enhanced magnetic field in which a magnetic field of the light is enhanced, in which magnetization of the magnetic recording medium is inverted by applying the external magnetic field and the enhanced magnetic field to the magnetic recording medium.

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 θr 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.

A magnetic tape in which an arithmetic average roughness Ra measured at a surface of the magnetic layer with an atomic force microscope is 2.0 nm or less, and in an environment with a temperature of 23° C. and a relative humidity of 50%, an AlFeSil abrasion value.sub.45° of a surface of the magnetic layer measured at a tilt angle of 45° of an AlFeSil prism is 20 μm to 50 μm, a standard deviation of an AlFeSil abrasion value of the surface of the magnetic layer measured at each of tilt angles of 0°, 15°, 30°, and 45° of the AlFeSil prism is 30 μm 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.

A magnetic recording medium including a magnetic layer including a ferromagnetic powder. The ferromagnetic powder is an ε-iron oxide powder, and a ratio of Hr (45°) to Hr (0°)(Hr (45°)/Hr (0°)) is 0.50 or less. The Hr (0°) is a residual coercive force Hr obtained by applying a pulse magnetic field having a pulse width of 0.76 ms in an in-plane direction of the magnetic recording medium, and the Hr (45°) is a residual coercive force Hr obtained by setting an angle of the magnetic recording medium in the in-plane direction to 0°, setting an angle of the magnetic recording medium in a vertical direction to 90°, and making a pulse magnetic field having a pulse width of 0.76 ms be incident from a direction inclined by 45° toward the vertical direction from the in-plane direction and applying the pulse magnetic field to the magnetic recording medium.