Magnetic recording medium

A magnetic recording cartridge comprising

• a cartridge case;
• a cartridge reel which is accommodated in the cartridge case;
• and
• a magnetic recording medium which is wound around the cartridge reel, the magnetic recording medium including
• a magnetic layer including a magnetic powder and a second binder,
• a non-magnetic layer including a non-magnetic powder and a second binder,
• a base layer including a polyester resin, and
• a back layer,
• wherein
• an average thickness tT of the magnetic recording medium is tT≤5.6 μm,
• a plurality of servo bands are formed along a longitudinal direction of the magnetic recording medium in the magnetic layer,
• a dimensional change amount Δw in a width direction of the magnetic recording medium with respect to a tension change in the longitudinal direction of the magnetic recording medium is 660 ppm/N≤Δw, wherein the dimensional change amount Δw is determined according to:
• Δ
• ⁢
• w
• [
• ppm
• /
• N
• ]
• =
• D
• ⁡
• (
• 0.2
• N
• )
• [
• mm
• ]
• -
• D
• ⁡
• (
• 1.
• 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, respectively, in the longitudinal direction of the magnetic recording medium at 25° C. and relative humidity 50% and a width of the sample of the magnetic recording medium is ½ inch prior to being subject to a load,
• a width deformation coefficient b during long-term storage in a case where a long-term
• storage width change amount Y is defined as Y=blog(t) is −0.06 μm≤b≤0.06 μm, wherein t≥50 hours, wherein the width deformation coefficient b is evaluated at 32° C. and relative humidity 55%.