Magnetic recording medium and magnetic recording and reproducing methods

摘要

A magnetic recording medium comprising a magnetic layer, a flexible support and a back coat layer in this order, wherein a density of spines on the back coat layer having a height of 100 nm or more measured with an atomic force microscope is from 50 to 200 in 90 mum square, and a thermal shrinkage factor in a machine direction after preservation at 70° C. 5% RH for 48 hours is 0.4% or less.