Magnetic tape, magnetic tape cartridge, and magnetic tape apparatus
The magnetic tape includes a non-magnetic support, and a magnetic layer containing a ferromagnetic powder, in which an absolute value ΔN of a difference between a refractive index Nxy measured in an in-plane direction of the magnetic layer and a refractive index Nz measured in a thickness direction of the magnetic layer is 0.25 or more and 0.40 or less, and standard deviation a of the ΔN in a width direction of the magnetic layer is 0.05 or less.
1 . A magnetic tape comprising:
a non-magnetic support; and
a magnetic layer containing a ferromagnetic powder,
wherein an absolute value ΔN of a difference between a refractive index Nxy measured in an in-plane direction of the magnetic layer and a refractive index Nz measured in a thickness direction of the magnetic layer is 0.25 or more and 0.40 or less, and
standard deviation a of the ΔN in a width direction of the magnetic layer is 0.05 or less.
2 . The magnetic tape according to claim 1 ,
wherein the standard deviation a of the ΔN is 0.02 or less.
3 . The magnetic tape according to claim 1 ,
wherein the standard deviation a of the ΔN is 0.01 or more and 0.02 or less.
4 . The magnetic tape according to claim 1 , further comprising:
a non-magnetic layer containing a non-magnetic powder between the non-magnetic support and the magnetic layer.
5 . The magnetic tape according to claim 4 ,
wherein the non-magnetic powder includes an Fe-based inorganic oxide powder having an average particle volume of 2.0×10 −6 μm 3 or less.
6 . The magnetic tape according to claim 4 ,
wherein the non-magnetic powder includes carbon black having a pH of 9.0 or less.
7 . The magnetic tape according to claim 4 ,
wherein a thickness of the non-magnetic layer is 0.1 μm or more and 0.7 μm or less.
8 . The magnetic tape according to claim 1 , further comprising:
a back coating layer containing a non-magnetic powder on a surface side of the non-magnetic support opposite to a surface side having the magnetic layer.
9 . The magnetic tape according to claim 1 ,
wherein a tape thickness is 5.2 μm or less.
10 . The magnetic tape according to claim 1 ,
wherein a tape thickness is 5.0 μm or less.
11 . The magnetic tape according to claim 1 ,
wherein a vertical squareness ratio of the magnetic tape is 0.60 or more.
12 . The magnetic tape according to claim 1 ,
wherein a vertical squareness ratio of the magnetic tape is 0.65 or more.
13 . The magnetic tape according to claim 1 ,
wherein the standard deviation a of the ΔN is 0.01 or more and 0.02 or less,
the magnetic tape further includes a non-magnetic layer containing a non-magnetic powder between the non-magnetic support and the magnetic layer,
the non-magnetic powder includes an Fe-based inorganic oxide powder having an average particle volume of 2.0×10 −6 μm 3 or less and carbon black having a pH of 9.0 or less,
a thickness of the non-magnetic layer is 0.1 μm or more and 0.7 μm or less,
the magnetic tape further includes a back coating layer containing a non-magnetic powder on a surface side of the non-magnetic support opposite to a surface side having the magnetic layer,
a tape thickness is 5.0 μm or less, and
a vertical squareness ratio of the magnetic tape is 0.65 or more.
14 . A magnetic tape cartridge comprising:
the magnetic tape according to claim 1 .
15 . A magnetic tape apparatus comprising:
the magnetic tape according to claim 1 .
16 . The magnetic tape apparatus according to claim 15 , further comprising:
a magnetic head,
wherein the magnetic head has a module including an element array with a plurality of magnetic head elements between a pair of servo signal reading elements, and
the magnetic tape apparatus changes an angle θ formed by an axis of the element array with respect to a width direction of the magnetic tape during running of the magnetic tape in the magnetic tape apparatus.