Magnetic recording medium having a dimensional variation
摘要
說明書
The Poisson's ratio ρ is determined as follows. First, the magnetic recording medium 10 with a ?-inch width is prepared, and cut out into a length of 150 mm to prepare a sample, and a central part of the sample is provided with a mark of 6 mm×6 mm in size. Next, both ends in the longitudinal direction of the sample are held with chucks such that the distance between the chucks is 100 mm, and with an initial load of 2 N applied, the length of the mark in the longitudinal direction of the sample in this case is regarded as an initial length, whereas the width of the mark in the width direction of the sample is regarded as an initial width. Subsequently, pulling is carried out in an Instron-type universal tensile testing device at a pulling speed of 0.5 mm/min, and the dimensional change amount is measured for each of the length of the mark in the longitudinal direction of the sample and the width of the mark in the width direction of the sample with an image sensor manufactured by Keyence Corporation. Thereafter, the Poisson's ratio ρ is determined from the following formula.
