Magnetic recording medium having a controlled dimensional variation

A magnetic recording cartridge comprising:

• a cartridge case,
• a single reel, and
• a magnetic recording medium, wherein
• the single reel wound with the magnetic recording medium is rotatably contained in the cartridge case and wherein
• the magnetic recording medium comprises
• a layer structure including a magnetic layer, a non-magnetic layer, and a base layer in this order, wherein
• an average thickness tT of the magnetic recording medium is 3.5 μm≤tT≤5.5 μm,
• the magnetic layer includes a plurality of servo bands along a longitudinal direction of the magnetic recording medium,
• the magnetic layer includes a magnetic powder and a first binder,
• the non-magnetic layer includes a non-magnetic powder and a second binder,
• the base layer includes polyester,
• a surface roughness Rabe of the base layer on a side of a back layer is 4.2 nm≤Rabe≤8.5 nm, and
• a dimensional variation Δw in a width direction of the magnetic recording medium to tension change in the longitudinal direction of the magnetic recording medium is 700 ppm/N≤Δw≤2000 ppm/N, and
• wherein the dimensional variation Δw is determined according to:
• Δ
• ⁢
• w
• [
• ppm/N]
• =
• D
• ⁡
• (
• 0.2
• ⁢
• ⁢
• N
• )
• ⁡
• [
• mm
• ]
• -
• D
• ⁡
• (
• 1.0
• ⁢
• ⁢
• N
• )
• ⁡
• [
• mm
• ]
• D
• ⁡
• (
• 0.2
• ⁢
• ⁢
• N
• )
• ⁡
• [
• mm
• ]
• ×
• 1,000,000
• (
• 1.0
• ⁡
• [
• N
• ]
• )
• -
• (
• 0.2
• ⁡
• [
• N
• ]
• )
• where D(0.2N) and D(1.0N) represent widths of a sample of the magnetic recording medium subject to loads of 0.2N and 1.0N at 25° C. and 50% RH, respectively, in the longitudinal direction of the magnetic recording medium and a width of the sample of the magnetic recording medium is ½ inch prior to being subject to a load at 25° C. and 50% RH.