Magnetic tape, magnetic tape cartridge, and magnetic tape apparatus

A magnetic tape comprising:

• a non-magnetic support;
• and
• a magnetic layer containing a ferromagnetic powder,
• wherein an arithmetic average roughness Ra measured on a surface of the magnetic layer is 1.5 nm or less,
• standard deviation σ of the Ra in a width direction of the surface of the magnetic layer is 0.20 nm or less, and
• a non-linear component of tape 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%.