Magnetic recording medium having a dimensional variation
摘要
說明書
The recording layer 13 is a so-called vertical recording layer, which includes, for example, a magnetic powder, a binder, and conductive particles. If necessary, the recording layer 13 may further include additives such as a lubricant, an abrasive, and a rust inhibitor.
The average thickness tm of the recording layer 13 preferably meets the requirement that 35 [nm]≤tm≤90 [nm]. When the average thickness tm of the recording layer 13 meets the requirement that 35 [nm]≤tm≤90 [nm], the electromagnetic conversion characteristics can be improved.
The average thickness tm of the recording layer 13 is determined as follows. First, the magnetic recording medium 10 is processed to be thin perpendicularly to the main surface, thereby preparing a sample piece, and the cross section of the test piece is observed with a transmission electron microscope (TEM) under the following conditions.
Equipment: TEM (H9000NAR manufactured by Hitachi, Ltd.)
Acceleration voltage: 300 kV
Magnification: 100,000-fold magnification
Next, with the use of the obtained TEM image, after measuring the thickness of the recording layer 13 at the positions of at least 10 points or more in the longitudinal direction of the magnetic recording medium 10, the measured values are simply averaged (arithmetic mean), and regarded as the average thickness tm (nm) of the recording layer 13.
(Magnetic Powder)
