PURPOSE: To obtain a vertical magnetic recording medium which is free from cracks with a small number of curls by setting the temperature of the circumferential side surface of a can of a vapor deposition mode at a proper level as well as the linear expansion coefficient of a substrate when a Ti film or the Ti film and a "Permalloy" film are vapor-deposited on the substrate made of a polymer material.
CONSTITUTION: A Co-Cr vertically magnetized film 2 for vertical magnetic recording is formed on a substrate 1 made of a polymer material via a Ti film 4. In this case, the Ti film 2 is formed by a vacuum vapor desposition process while traveling along the circumferential side surface of a cylindrical can 6. In this case, the linear expansion coefficient of the substrate 1 requires 1.0× 10-5W2.9×10-5/°C. At the same time, the temperature of the circumferential surface of the can 6 is set at 10W120°C. It is possible to obtain a film having (l0-l)/l0 set at ≤6% under the above-mentioned conditions, where l shows the length in a curled state and l0 shows the length in a non-curled state, respectively. The same result is obtained with the film thickness of the substrate 1 set within a range of 9W26μm with the film 4 set in a range of 300W1,500 respectively.
KANAI KENJI
SASAKI KIYOSHI
TAKAHASHI TAKESHI
