Magnetic tape, magnetic tape cartridge, and magnetic tape apparatus

A magnetic tape comprising:

• a non-magnetic support;
• a magnetic layer containing a ferromagnetic powder;
• a non-magnetic layer containing a non-magnetic powder between the non-magnetic support and the magnetic layer;
• and
• 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,
• wherein the ferromagnetic powder is one or more ferromagnetic powders selected from the group consisting of hexagonal barium ferrite powder, hexagonal strontium ferrite powder, and ε-iron oxide powder, and
• a non-linear component of tape width deformation generated by storage for 10 days in an environment of a temperature of 60° C. and a relative humidity of 20% is 100 nm or less,
• said non-linear component of tape width deformation being determined from an absolute value of a difference between (i) a non-linear component of tape width deformation at an initial stage where the magnetic tape is wound around a reel and stored for 24 hours or longer at 20° C. to 25° C. and a relative humidity of 40% to 60% and (ii) a non-linear component of tape width deformation after storage for 10 days at 60° C. and a relative humidity of 20%.